Robustness analysis and synthesis of SISO systems under both plant and controller perturbations

In this paper, we consider the robustness analysis and synthesis problem fo r a class of control systems under both plant and controller perturbations. Necessary and sufficient conditions are given for robust stability of SISO systems subject to additive norm-bounded perturbations. Linear matrix ineq uality (LMI)-based controller design method is presented. Robust stability of systems with both plant and controller perturbations, and stability anal ysis of a class of multilinear disc polynomials are unified in the same fra mework, and can be solved by computing the largest norm of a second-order m atrix along the imaginary axis. (C) 2001 Elsevier Science B.V. All rights r eserved.