Observer-based positive real control of uncertain linear systems

This paper is concerned with the positive control problem for a class of linear systems with norm-bounded uncertainties. We address the problem of designing observer-based dynamic output-feedback controllers that robustly stabilize the uncertain system and achieve the extended strict positive realness for a given closed-loop transfer function. By casting the problem at hand into a class of strict positive real control problems with scaling parameters, an uncertainty-independent solution is then establised and expressed in linear matrix inequalities format.