A Unified Fuzzy Control Approach for Stochastic High-Order Nonlinear Systems With or Without State Constraints
Yangang Yao, Jieqing Tan, Jian Wu, Xu Zhang
Abstract
A unified approach to fixed-time tracking control of stochastic high-order nonlinear systems (HONSs) with or without full-state constraints is studied in this article. By introducing two important universal-constrained functions and using coordinate transformation technology, the stochastic HONS with full-state constraints is transformed into an equivalent one without state constraints. Compared with the existing control schemes, the proposed scheme not only eliminates the feasibility conditions, but also accurately analyzes the scope of tracking error. Moreover, the limitation that the constraint functions need to be bounded is also removed; thus, the proposed scheme is a unified approach that can be applied to stochastic HONSs with or without state constraints. With the help of fixed-time stability theory and adaptive fuzzy control technology, a novel fixed-time fuzzy controller is designed. In addition, an adaptive event-triggering mechanism that the threshold parameters can be adjusted adaptively according to the tracking performance is introduced to reduce the communication burden. Simulation results verify the scheme developed.