Robust stabilization for the plant with varying number of unstable poles and low sensitivity characteristics

We consider the robust stability condition for single-input single-output continuous time invariant systems with varying number of unstable poles. First, we define a class of uncertainty to be considered. The necessary and sufficient robust stability condition for the system with such class of uncertainty is presented. The relation between the plant and the nominal plant that is included in such class of uncertainty, is clarified. By using this relation, we show the necessary and sufficient robust stability condition for the system with varying number of right half plane poles. In this framework, we can construct the control system with low sensitivity characteristics and robustly stable