This paper considers the problem of guaranteed cost control for discrete-time linear systems under state feedback control gain perturbations. Two classes of perturbations are considered, namely, additive and multiplicative. The state feedback control designs for optimal guaranteed cost control under the two classes of gain perturbations are given in terms of solutions to algebraic Riccati equations. The designs are such that the cost of the closed-loop system is guaranteed to be within a certain bound for all admissible uncertainties. Numerical examples are included to illustrate the design procedures.

This paper is concerned with decentralized robust control design for a class of interconnected systems with time-varying uncertainties. The interconnected systems under consideration contain time-varying uncertain parameters whose values are unknown but bounded in given compact sets. Sufficient conditions under which a considered system can be quadratically stabilized by a linear decentralized feedback control for all admissible variations of uncertainties are given in terms of the structures of uncertainties. For the interconnected systems satisfying the stabilizability conditions, a decentralized control design procedure is also provided.

This paper considers the problem of decentralized H∞ controller design via measurement feedback for linear composite systems. Two decentralized controller design procedures are presented in terms of positive definite solutions to modified algebraic Riccati inequalities. The resulting controllers guarantee closed-loop stability and an H∞-norm bound on disturbance attenuation. A numerical example is given to illustrate the design procedures.

This paper considers the decentralized H∞-controller design problem for nonlinear systems. Sufficient conditions for the solution of the problem are presented in terms of solutions of Hamilton-Jacobi inequalities. The resulting design guarantees local asymptotic stability and ensures a predetermined L2-gain bound on the closed-loop system.