On interpolation with units in H∞

The problem of finding a unit in H_∞ i.e., an H _∞ function the inverse of which is also H_∞ , which interpolates to given points in the right-half plane has important applications in a number of feedback stabilization problems, i.e., strong stabilization (stabilization by a stable compensator) and simultaneous stabilization (finding a common fixed compensator which stabilizes a finite set of possible plants). The present paper gives an overview of the interpolation theory and some remarks observed with different mappings used in literature to find a unit in H_∞ . A new algorithm is also presented to construct a unit in H_∞