Design of H∞-optimal robust controllers: Stability, asymptotic regulation and disturbance rejection

This paper introduces a new synthesis method, based on a computation method for solving a H??-optimization problem1 and a new technique of "j-axis shifting" for designing a H^∞ optimal robust controller for the SISO system. With this method, we can optimize the excess stability margin under the requirement that all poles of the nominal closed loop system (cl-system) be located at the left of the j-axis with a required distance d and ensure asymptotic regulation and disturbance rejection for a class of system input and disturbance if the plant perturbation does not exceed the excess stability margin. Another advantage is that there are no constraints to the poles and zeros of the plant when using this method.