Journal of Process Control, Vol.21, No.1, 82-91, 2011
Using uncertain prior knowledge to improve identified nonlinear dynamic models
This paper addresses the parameter-estimation problem for linear-in-the-parameter nonlinear models for the case in which uncertain prior knowledge is available in the form of noisy steady-state data. An uncertainty-weighted least-squares (UWLS) algorithm is developed which takes into account not only the dynamical and the steady-state data but also a measure of relative uncertainty of both data sets. Also, it is shown that a previously developed bi-objective optimization estimator is a special case of UWLS. A consequence of this is that UWLS can take advantage of tools developed in the context of multiobjective optimization to automatically determine an adequate relative uncertainty measure for dynamical and steady-state data sets. The developed algorithm and related ideas are investigated and illustrated by means of examples that use simulated and measured data. (C) 2010 Elsevier Ltd. All rights reserved.
Keywords:Gray-box modeling;Nonlinear system identification;Uncertain steady-state data;NARMAX models;Least squares