Event-triggered-based fuzzy adaptive tracking control for nonstrict-feedback asymmetric state constrained systems

Abstract

In this article, a fuzzy adaptive command filtered event-triggered control issue is considered for a category of nonstrict-feedback nonlinear systems under the conditions of asymmetric state constraints and time-varying input delay. Firstly, the nonlinear state constrained system is transformed into a new system without state constraints by utilizing nonlinear mappings, which achieves state constraints while removing the feasibility conditions of virtual control signals. Secondly, unknown nonlinear terms in the novel system are approached by using the fuzzy logic systems, a state observer is established to estimate the unmeasurable states in the system, and an auxiliary system is constructed to make up for the influence of time-varying input delay. In addition, the command filtered technology is introduced to overcome the complexity explosion problem in the conventional backstepping design process. It is shown that the fuzzy adaptive event-triggered control scheme can not only ensure the convergence of the tracking error at the origin and the boundedness of all closed-loop signals, but also lighten the communication burden from the controller to the actuator. Finally, a numerical example and an underwater vehicle system are simulated to verify the availability and feasibility of the developed approach.