Fuzzy-model-based decentralized dynamic-output-feedback H ∞ control for large-scale nonlinear systems with time-varying delays

Abstract

This paper concerns the problem of decentralized dynamic output feedback (DOF) H∞ control for large-scale nonlinear systems with nonlinear interconnections and time-varying delays. Each nonlinear subsystem in the considered large-scale system is represented by a Takagi–Sugeno (T–S) model, and the time delay of each subsystem is assumed to be of an interval-like type. We propose a model transformation to reformulate the decentralized DOF H∞ control problem into the context of input–output (IO) stability. By introducing a Lyapunov–Krasovskii functional (LKF) that all Lyapunov matrices are not required to be positive definite, and combining with the scaled small gain (SSG) theorem, less conservative results to the decentralized DOF H∞ controller design of the large-scale T–S fuzzy system are derived in terms of linear matrix inequalities (LMIs). Two numerical examples are given to validate the advantage of the proposed method.