Smooth robust adaptive sliding mode control of manipulators with guaranteed transient performance

Abstract

A systematic way to combine an adaptive control design technique and sliding mode control methodology for trajectory tracking control of robot manipulators in the presence of parametric uncertainties and external disturbance is developed in this paper. Continuous sliding mode controllers without the unpleasant reaching transient and chattering problem are first developed by using a dynamic sliding mode. Transient performance is guaranteed and globally uniform ultimate boundedness (GUUB) stability is obtained. A conventional adaptive scheme is also developed for comparison. With some modifications to the conventional adaptation law, the control law is redesigned by combining the design methodologies of adaptive control and sliding mode control. The suggested controller preserves the advantages of both methods, namely, asymptotic stability of adaptive systems for parametric uncertainties and GUUB stability with guaranteed transient performance of sliding mode control for both parametric uncertainties and external disturbances. The control law is continuous and the chattering problem of sliding mode control is avoided. A priori knowledge of the bounds of the parameter uncertainties and external disturbances is assumed. Experimental results illustrate the effectiveness of the proposed methods.