Abstract:

An adaptive robust positioning control scheme is produced for a class of multivariable nonlinear systems with some modeling error and unknown uncertainties. The multivariable systems are composed of some subsystems, and the uncertainties are assumed to be normbounded, but the upper bound is unknown. Based on the Lyapunov theory and the Barbalat lemma, the synthetical design procedures for the sliding mode controller and the adaptive law are given, when the system mathematical models are known or unknown, respectively, so that the closedloop error systems are stable. This method reduces the dependence on the precision of systems，also, the traditional and contrived estimation of the uncertainty is avoided. Simulation of the ship with dynamic positioning control systems show the effectiveness of the proposed method.