On the Robust H/spl infin/ Reduced-Order Unknown-Input Filtering Problem for a Class of Uncertain Linear Neutral Systems

In this paper, existence and design of reduced-order robust H_infin filters for a class of neutral systems are addressed. We focus in particular on systems subjected to parametric uncertainties and unknown inputs. Thanks to the descriptor system approach and several algebraic manipulations, we shall establish that the existence of such filters is guaranteed when certain necessary and sufficient conditions are fulfilled. Thereafter, based on the Krasovskii stability theorem, it is shown that the design of such filters is tuned into a feasibility problem of some reduced-order linear matrix inequalities. Finally, we present an illustrative example to show the effectiveness of the obtained results