Iterative method for designing an observer-based mixed H2/D-stability controller

This paper treats the output feedback H₂ control with regional pole placement condition. In general, this problem is a BMI problem which is difficult to be solved theoretically. The purpose of this paper is to propose an iterative method for obtaining a sub-optimal solution of the H₂ control problem with regional pole placement condition. The key idea of this paper is to employ a full-order observer-based controller. The proposed method produces a sequence of controllers which approaches to the unconstrained globally optimal H₂ controller while it satisfies the D-stability constraint. A numerical example shows the effectiveness of our method