Optimization in the process industry has received a lot of attention in recent years because, in the face of growing competition, it represents a natural choice for reducing production costs, improving product quality, and meeting safety requirements and environmental regulations. Traditionally, the optimal operating conditions are determined on the basis of a model of the process. However, the resulting process operation can be highly sensitive to uncertainty such as process-model mismatch and process disturbances. This generally gives rise to suboptimal process operation or, worse, infeasible operation, which of course is not acceptable in most industrial applications. Over the last decade, the Laboratoire 'Automatique of EPFL has developed a promising approach that converts a dynamic optimization problem with both path and terminal constraints into a feedback control problem. In this approach, near-optimal process operation can be enforced by tracking appropriate references, namely the necessary conditions of optimality (NCO). The NCO-tracking methodology is appealing in its on-line simplicity and potential to be robust towards uncertainty. This presentation will start with a tutorial overview of dynamic optimization in the presence of uncertainty. The main discussion will concern ways of dealing with plantmodel uncertainty via appropriate modeling. Also, a systematic procedure for devising NCO-tracking controllers will be described and illustrated through several case studies.
Dominique Bonvin is Professor of Automatic Control at Ecole Polytechnique Fédérale de Lausanne (EPFL). He received his Diploma in Chemical Engineering from the ETH, Zürich, and his Ph.D. degree from the University of California, Santa Barbara. He worked in the field of process control for the Sandoz Corporation in Basel and with the Systems Engineering Group of ETH Zürich. He joined the EPFL in 1989, where his current research interests include modeling, identification and optimization of dynamic systems as well as process chemometrics. He served as Director of the Laboratoire d'Automatique for the periods 1993-97 and 2003-2007, Head of the Mechanical Engineering Department in 1995-97 and Dean of Bachelor and Master Studies at EPFL for the period 2004-2011.
