Nonfragile Observer‐Based Tracking Control for Unmanned Surface Vessels in Discrete‐Time Complex Dynamics With Time‐Delay and Markovian Switching

ABSTRACT In this paper, a nonfragile observer‐based control strategy is provided, which addresses the dual challenges of networked unmanned surface vessels (USVs) systems with time‐delay and Markovian switching under discrete‐time complex dynamic environments. First, to model the system accurately, the underactuated USV model is converted into a cascade form that is discretized using Euler's discretization method, establishing the system equation and effectively decoupling the complex nonlinear interactions. Furthermore, considering disturbances such as wind, waves, currents, time delays and random switching mechanisms, a state‐space framework of the Takagi‐Sugeno (T‐S) fuzzy dynamics plant with Markovian switching is presented comprehensively. In addition, the observer is designed and nonfragile observer‐based controller is provided to theoretically guarantee that the closed‐loop system is globally, asymptotically mean‐square stable via rigorous Lyapunov‐based analysis and linear matrix inequalities (LMIs). Lastly, numerical validations are carried out, and the comparative assessments demonstrate that the proposed method achieves superior tracking accuracy and robustness compared to traditional controllers.