Chattering-free sliding mode control for a class of nonlinear mechanical systems

Second-order sliding mode control (2-smc) and dynamic sliding mode control (dsmc) eliminate the disturbing characteristic of chattering in static sliding mode control under the assumption that the derivative of the sliding surface is available or complex inequalities at the acceleration level can be constructed. In this paper, passivity-based adaptive and non-adaptive chattering-free sliding mode controllers are proposed assuming that the upper bound of the norm of the derivative of the sliding surface is available, a weaker and easy to implement assumption in comparison to those of 2-smc and dsmc. The closed-loop system accounts explicitly for the invariance condition without reaching phase, and therefore far a desired transient response with global exponential convergence of tracking errors. Preliminary experiments are presented. Copyright (C) 2001 John Wiley & Sons, Ltd.