Uncertainty and Disturbance Estimator-Based Tracking Control for Fuzzy Systems

In this paper, a novel robust tracking control scheme is developed for a class of Takagi-Sugeno fuzzy systems subject to completely unknown perturbed dynamics and unknown external disturbances. The main objective of this paper is to simultaneously reject the lumped disturbance and asymptotically track a prescribed reference signal by the system states. First, the uncertainty and disturbance estimator (UDE) algorithm is used to estimate and cancel out the unknown lumped disturbance effect. The concept behind the UDE algorithm is that a signal can be approximated and estimated by using a filter with the appropriate bandwidth. Then, the tracking control problem of considered fuzzy system is equivalently transformed into the stability problem of an error system. Finally, two numerical examples with simulations are provided to illustrate the effectiveness and applications of the proposed control scheme.