Output-feedback control of uncertain nonlinear systems using adaptive fuzzy observer

In this paper, a robust adaptive controller based on fuzzy observer for a class of unknown nonlinear systems with bounded external disturbances is presented. Firstly, a fuzzy observer based on fuzzy-basis-functions is designed to estimate the system state variables, and the fuzzy observer can guarantee the uniform ultimate bounds of the observer errors by SPR theory. Secondly, the adaptive controller with a fuzzy observer which requires only the system output variable is showed to control a class of unknown nonlinear systems with external disturbances, and the adaptive controller can guarantee the uniform ultimate bounds of the tracking errors. Finally, this simulation results presented adaptive controller applied to a single link robot control system demonstrate and confirm the effectiveness of the proposed method.