Reduced-order observer for systems with piecewise constant inputs

The problem of reduced-order state estimators for systems with deterministi c, i.e. known input is considered. Since below a certain order exact tracki ng of the state with reduced-order estimator is, in general, impossible, th e approximation should take into account the class of expected inputs. In t his paper a reduced-order estimator is designed for systems subjected to in puts consisting of set functions with varying amplitudes. The estimation er ror is required to be zero at steady state and its transient is minimized i n the L-2 sense. The optimal estimator is given explicitly and its structur e is determined by three projection matrices. Copyright (C) 1999 John Wiley & Sons, Ltd.