Observer-Based Finite-Time Adaptive Fuzzy Control with Prescribed Performance for Nonstrict-Feedback Nonlinear Systems

This paper considers the problem of finite-time adaptive fuzzy prescribed performance control via output-feedback for nonstrict-feedback nonlinear systems. The fuzzy state observer is designed to estimate the unmeasured system states. To rapidly approximate the derivative of virtual signal, a novel finite-time command filter is proposed. The fractional power error compensation mechanism is established to remove filtered error. By integrating the prescribed performance control and command filter technique into backstepping recursive design, a finite-time adaptive output-feedback controller is constructed, and the stability of closed-loop system is strictly proved. The designed control strategy shows that the closed-loop system is practical finite-time stable, and the output tracking error converges to a residual set within prescribed performance bound in finite time. Finally, a numerical comparison and a practical examples are provided to demonstrate the validity of the developed finite-time control algorithm.