A hybrid nonlinear state observer for concentration profiles reconstruction in nonlinear simulated moving bed

In this paper, a state observer is proposed for the reconstruction of the concentration profiles in a simulated moving bed. The approach is based on a simple Luenberger-like correction term. The observer is used under the assumption that the flow rates are constant during each switching period. The matrix gain of the correction term may then be re-computed at the beginning of each switching period corresponding to flow rates being changed by the controller. Validating simulations are proposed to assess the efficiency of the proposed profile reconstruction and its robustness against uncertainties on modelling parameters. Comparisons are also done with open-loop simulation based-observer in order to strengthen the relevance of the correction term. (C) 2005 Elsevier Ltd. All rights reserved.