This paper addresses the reliable H∞-control problems for affine nonlinear systems. Based on the Hamilton-Jacobi inequality approach developed in the H∞-control problems for affine nonlinear systems, a method for the design of reliable nonlinear control systems is presented. The resulting nonlinear control systems are reliable in that they provide guaranteed local asymptotic stability and H∞ performance not only when all control components are operational, but also in the case of some component outages within a prespecified subset of control components. A numerical example is also given. H∞ control, Hamilton-Jacobi inequalities, nonlinear systems, reliable control.

This paper discusses a class of large-scale systems composed of several similar subsystems interconnected with an external system in a symmetrical fashion. A method of determining the set of fixed modes of such a system with respect to decentralized (or partly decentralized) control is presented in terms of the modified subsystems. The completeness of these systems is studied, and a simple condition for such a system to be complete is derived.

This paper is concerned with the problem of suboptimal stable mixed H2/H∞ control for linear time-invariant systems. The designed controller with the same order as that of the considered system is required to satisfy a prescribed H∞ performance bound or a prescribed degree of stability. By reducing the stable controller synthesis problem to a multiobjective state feedback control problem for two different state models, sufficient conditions for the solvability of the considered problem are given in terms of solutions to algebraic Riccati equations and matrix inequalities. An LMI-based iterative algorithm is developed to solve the stable controller synthesis problem. The proposed algorithm is shown to be convergent. Examples are given to illustrate the proposed methods.

This paper discusses the problem of designing stabilizing controllers for uncertain symmetric composite systems. A procedure of designing a linear (decentralized) feedback control law which will stabilize a given symmetric composite system with uncertainty is presented by using the Riccati equation approach. A feature of the procedure is that the stabilizing control law can be conducted by solving two lower-order Riccati equations (or inequalities). The uncertainties considered in the systems may be time-varying. However, the values of the uncertaintics are constrained to lie within some known admissible bounds.

This note is concerned with the problem of a robust non-fragile Kalman filter design for a class of uncertain linear systems with norm-bounded uncertainties. The designed state estimator can tolerate multiplicative uncertainties in the state estimator gain matrix. The robust nonfragile state estimator designs are given in terms of solutions to algebraic Riccati equations. The designs guarantee known upper bounds on the steady-state error covariance. A numerical example is given to illustrate the results.