Abstract

CUEVAS-ORTIZ, F.A.; NERIA-GONZALEZ, M.I.  and  AGUILAR-LOPEZ, R.. Nonlinear observer for switched systems: application to a batch bioreactor. Rev. Mex. Ing. Quím [online]. 2015, vol.14, n.1, pp.137-147. ISSN 1665-2738.

The main objective of this work is to design a new state observer for a switched nonlinear system. The proposed observer contains a standard proportional term and a bounded feedback that improves the performance of the estimation process compared with other methodologies such as extended Luenberger-type observers. A theoretical analysis of the convergence of the proposed observer through an analysis of multiple Lyapunov functions is provided. The estimation strategy is applied to a bioreactor batch, where is performed a process of sulfate-reducing considering a hypothetical change in kinetic regime. The evolution of the reaction kinetics is described in three stages: the first stage is described by the Haldane-Boulton kinetic model; the second transitional stage called an interaction between the Haldane-Boulton and Moser-Boulton kinetic models; and the third stage is represented by the model Moser-Boulton. Sulfide concentration is considered as a measured variable of the bioreactor to implement the proposed observer. Numerical experiment results shown satisfactory performance of the considered methodology.

Keywords : nonlinear observer; switched system; adaptive modeling; batch bioreactor.

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