Stability margin optimization via interpolation and conformal mappings

Many interesting problems of robust stabilization can be solved using the complex function theoretic approach of Khargonekar and Tannenbaum (1985). This method is based on the construction of a conformal mapping which reduces the original robust stabilization problem to a Nevanlinna-Pick interpolation problem. The main difficulty of this approach lies in the construction the conformal mapping. The authors present a new numerical algorithm to construct such conformal mappings. Then they demonstrate its effectiveness in the synthesis of optimal gain-phase margin controllers