Observer-Based Robust Adaptive Fuzzy Control for Uncertain Underactuated Systems with Time Delay and Dead-Zone Input

This paper investigates the observer-based robust adaptive fuzzy control problem for a class of uncertain underactuated systems with time delay and dead-zone input. Within this method, the state observer is developed for estimating the unmeasured states in the underactuated system. The fuzzy logic systems are used to approximate the unknown nonlinear functions, and some adaptive laws are introduced to estimate unknown parameters. The dead-zone input which is one of the significant input constraints often exists in many practical industrial control systems. By employing a Lyapunov-Krasovskii functional, it is verified that the proposed controller ensures that all the signals in the closed-loop system are bounded. Simulation results are illustrated to demonstrate the regulation performance of the system output and state estimation by the proposed control method.