SIMPLIFYING H-INFINITY CONTROLLER SYNTHESIS VIA CLASSICAL FEEDBACK-SYSTEM STRUCTURE

Recently, H∞-optimal controller synthesis problem has been shown to lead to the solution of two algebraic Riccati equations. This note explores the properties of this solution in the framework of the classical cascade controller feedback structure. In addition to allowing effective tradeoff between significant closed-loop transfer functions, this system structure is shown to substantially simplify controller computation in the practically important case of open-loop stable plant and weights in that at most one Riccati equation needs to be solved. © 1990 IEEE