A sufficient condition for output feedback stabilization of uncertain dynamical systems

A different proof than the one given by E. Zeheb (ibid., vol.AC-31, p.1055-7, Nov. 1986) is given for the existence of an output feedback controller which stabilizes an uncertain single-input/single-output dynamical system with a linear nominal part and matched uncertainties. However, there is no need to assume that the nominal system is stable. A simple expression is obtained for the feedback gain which is necessary for the closed-loop nominal system to become strictly positive real.<
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