Delay effects on static output feedback stabilization

This paper addresses conditions for characterizing static output feedback controllers including delays for some proper (finite-dimensional) transfer functions. The interest of such study is in controlling systems which can not be stabilized by the classical, non-delayed static output feedback, and its difficulty lies in computing delay intervals guaranteeing closed-loop stability, since stability switches/reversals may occur for the same (matrix) gain if the delay is seen as `free´ (design) parameter. The derived conditions are expressed in terms of some appropriate matrix pencils or MIMO Nyquist tests. Illustrative examples are also presented