ADAPTIVE ROBUST-CONTROL OF SISO NONLINEAR-SYSTEMS IN A SEMI-STRICT FEEDBACK FORM

This paper considers the adaptive robust control of a class SISO nonli near systems in a semi-strict feedback form. The systems may possess b oth parametric uncertainties and unknown nonlinear functions that may represent modeling errors and external disturbances. With prior knowle dge of the bounds of the parametric uncertainties and the bounding fun ctions of the unknown nonlinear functions, a systematic way to combine the backstepping adaptive control with deterministic robust control i s developed. The method preserves the advantages of the two methods, n amely asymptotic stability of adaptive control in the presence of para metric uncertainties, and guaranteed transient performance with prescr ibed precision of deterministic robust control for both parametric unc ertainties and unknown nonlinear functions. The resulting controller i s more flexible and Versatile than either adaptive control or robust c ontrol alone. Simulation results verify the advantages of the suggeste d method. (C) 1997 Elsevier Science Ltd.