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Nonlinear input transformations for disturbance rejection, decoupling and linearization
October 5, 2020 @ 1:30 pm - 3:00 pm
Link para a apresentação: https://meet.google.com/dhh-bgyv-grj
Abstract. The goal of my research is to develop simple yet rigorous methods to solve problems of engineering significance. The topic of input transformations is something I have been working on for the last year or so, and I think it has a lot of promise. The starting point is that I observed that industry frequently used static model-based calculation blocks for various purposes, such as counteracting nonlinearity, disturbances and coupling. Industry also frequently uses cascade control.
However, there is little theory for when to use these solutions, and we have found that the use of input transformations forms a good basis. The starting point is a nonlinear process model, which is transformed to a simpler model through the use of an input transformation. It is really very simple. Consider a nonlinear model dy/dt=f(y,u,d) and introduce v=f(y,u,d) as the transformed input to get a nonlinear transformed system dy/dt=v which is linear, decoupled and independent of disturbances. This transformation is a special case of feedback linearization, but we have extended the idea by adding a tuning parameter, by allowing for static process models and by making use of cascade control in a systematic way. The method has been tested on many process control examples.
Minibio
Sigurd Skogestad is a professor in chemical engineering at the Norwegian University of Science and Technology (NTNU) in Trondheim. Born in Norway in 1955, he received the Siv.Ing. degree (M.S.) in chemical engineering at NTNU in 1978. After finishing his military service at the Norwegian Defence Research Institute, he worked from 1980 to 1983 with Norsk Hydro in the areas of process design, thermodynamics and simulation at their Research Center in Porsgrunn, Norway. Moving to the US, he worked 3.5 years under the guidance of Manfred Morari, receiving the Ph.D. degree from the California Institute of Technology in 1987. He has been a full professor at NTNU since 1987. During the period 1999 to 2009 he was Head of Department of Chemical Engineering ( Kjemisk prosessteknologi ). Since 2015 he is the Director of SUBPRO, a multi-disciplinary center on subsea technology at NTNU.
He was at sabattical leave at the University of California at Berkeley in 1994-95, and at the University of California at Santa Barbara in 2001-02.
The author of more than 200 international journal publications and more than 200 conference publications, he is the principal author together with Ian Postlethwaiteof the book “Multivariable feedback control” published by Wiley in 1996 (first edition) and 2005 (second edition). Dr. Skogestad was awarded “Innstilling to the King” for his Siv.Ing. degree in 1979, a Fullbright fellowship in1983, received the Ted Peterson Award from AIChE in 1989, the George S. Axelby Outstanding Paper Award from IEEE in 1990, the O. Hugo Schuck Best Paper Award from the American Automatic Control Council in 1992, and the Best Paper of the Year 2004 Award from Computers and Chemical Engineering. He was an Editor of Automatica during the period 1996-2002, was a member of the International Federation of Automatic Control (IFAC) Technical Board from 2008 to 2014, and became an IFAC Fellow in 2014. He is a Fellow of the American Institute of Chemical Engineers (2012) and was elected into the Process Control Hall of Fame in 2011.He is an honorary member of Norwegian Society of Automatic Control (2015) and was elected as member of The Norwegian Academy of Science and Letters, Oslo in 2015. he is an Honorary member of Norwegian Society of Automatic Control (Norsk Forening for Automatisering) (2015). More recently, he received (together with Cristina Zorica) the Best paper award at the ESCAPE 2019 Symposium (Eindhoven, June 2019) and received the Computing in chemical engineering award from the American Institute of Chemical Engineers (Orlando, 12 Nov. 2019).
Professor Skogestad has graduated more than 40 PhD candidates. He presently has a group of about 6 Ph.D. students. He is since 2015 Director of SUBPRO, a research-based innovation center in subsea production and processing at NTNU, funded by the by the Research Council of Norway and industry, and with a budget of about 35 million NOK per year (2015-2023). He is also the leader of PROST which is the strong point center in process systems engineering in Trondheim and involves about 50 people in various departments.
The goal of his research is to develop simple yet rigorous methods to solve problems of engineering significance. Research interests include the use of feedback as a tool to (1) reduce uncertainty (including robust control), (2) change the system dynamics (including stabilization), and (3) generally make systema more well-behaved (including self-optimizing control). Other interests include limitations on performance in linear systems, control structure design and plantwide control, interactions between process design and control, and distillation column design, control and dynamics. His other main interests are mountain skiing (cross country), orienteering (running around with a map) and grouse hunting.
See also: https://folk.ntnu.no/skoge/