Parameter Extimation in Extended Kalman Filters for Quality Control in Polymerization Reactors

The issue of parameter estimation in Extended Kalman Filters is addressed in this paper. It is shown that the use of parameters as additional system states is appropriate whenever there are systematic errors in the model of the process. Such is the case of the filters which are used to estimate quality properties of polymers which are not measured on-line in polymerization reactors. Criteria for the choice of the parameters to be updated are suggested. Moreover, in order to realize the possibility of obtaining offset free response, the effect of errors on both updated and not updated parameters, both on the observable and on the unobservable system states is analysed. Applications to the polymerization of methylmethacrylate (MMA) in a continuous stirred tank reactor confirm the theoretical results