LAUSR

Abstract This paper investigates the prescribed performance tracking control problem for a class of feedback linearizable multi-input and multi-output (MIMO) nonlinear systems with immeasurable states and unknown control direction. The fuzzy systems are employed to approximate the unknown nonlinear functions, an adaptive fuzzy state observer is developed to estimate the unmeasured states. By utilizing the state observer, an adaptive fuzzy output-feedback controller equipped with the Nussbaum-type function is developed to solve the unknown control direction issues. It is proved that all the signals in the closed-loop systems are bounded and that the prescribed performance error constraints can be achieved. Simulation examples are provided to highlight the effectiveness of the proposed approach.