Sensitivity Shaping under Degree Constraint: Bi-Tangential Nevanlinna-Pick Interpolation with a Complexity Constraint Approach

A solution to the bi-tangential Nevanlinna-Pick interpolation with a complexity constraint is presented. The solution can be described by the ratio of functions, PsiQ^-1, similar to the previous works. It is obtained by minimizing a strictly convex functional. The essence in the present work lies in the construction of the domain of Q. The theory is applied to a sensitivity shaping problem, and a certain class of the free design parameter Psi is suggested to obtain a controller of low degree