The problem of observer‐based decentralized robust H_∞ output tracking control with preview action in a class of uncertain and disturbed nonlinear interconnected systems is investigated in this study. The considered interconnected system consists of several subsystems with nonlinear interconnections, parametric uncertainties, and external disturbances. Based on the augmented error system approach combined with Lyapunov stability theory and special matrix inequality linearization techniques, a sufficient condition for the existence of a decentralized observer‐based robust H_∞ output feedback preview controller is derived for the original interconnected system in terms of linear matrix inequality (LMI) formulations. The gain matrices of the tracking controller and state observer are derived using only a one‐step LMI procedure, which overcomes the drawbacks of some multistep iterative algorithms. Finally, the effectiveness of the proposed control scheme is validated using a numerical example.

In this paper, the preview tracking control problem for Lipschitz nonlinear system, where future reference signals over a finite horizon can be previewed. First, an augmented error system including previewed information is constructed, which transforms a preview tracking control problem into a regulation problem. Furthermore, sufficient conditions on polytopic nonlinear systems, which guarantee the corresponding closed-loop system to be asymptotically stable, are derived by employing parameter-dependent Lyapunov function. A linear matrix inequality approach for designing preview controllers in state feedback and output feedback settings is presented. Finally, two numerical examples are provided to demonstrate the effectiveness of the proposed approach.

Purpose: Considering the unmeasurable states of the systems and the previewed reference signal, a novel fuzzy observer-based preview controller, which is a mixed controller of the fuzzy observer-based controller, fuzzy integrator and preview controller, is considered to address the tracking control problem.Design/methodology/approach: The authors employ an augmentation technique to construct an augmented error system for uncertain T-S fuzzy discrete-time systems with time-varying uncertainties. Additionally, the authors obtain the corresponding linear matrix inequality (LMI) conditions for designing the preview controller.Findings: This paper discusses the preview tracking problem for nonlinear systems. First, considering the unmeasurable states of the systems and the previewed reference signal, a novel fuzzy observer-based preview controller, which is a mixed controller of the fuzzy observer-based controller, fuzzy integrator, and preview controller, is considered to address the tracking control problem. Then, using the fuzzy Lyapunov functional with the linear matrix inequality (LMI) technique, new sufficient conditions for the asymptotic stability of the augmented system are derived by applying the LMI technique. The preview controller and fuzzy observer can be designed in one step. Finally, a numerical example is used to illustrate the effectiveness of the results.Originality/value: An augmented error system is successfully constructed by the state augmentation approach. A novel preview controller is designed to address the tracking control problem. The preview controller and fuzzy observer can be designed in one step.