ROBUST ADAPTIVE TRACKING CONTROL FOR A CLASS OF PERTURBED UNCERTAIN NONLINEAR SYSTEMS

Abstract

A novel robust adaptive controller is presented for a wide class of strict feedback uncertain nonlinear system with unknown virtual control coefficients under bounded exogenous disturbances. Combined Nussbaum gain with the backstepping technique, the proposed design algorithm, which does not require a priori knowledge of the signs of the unknown virtual control coefficients, is proved to be able to guarantee the resulting closed-loop system globally uniformly ultimately bounded (GUUB). Moreover, the output of the system is proven to converge to a small neighborhood of the origin. Simulation results are presented to validate the effectiveness of the proposed controller.