AN INTELLIGENT SLIDING MODE CONTROLLER FOR UNDERACTUATED MECHANICAL SYSTEMS

Abstract

This paper presents an intelligent controller for uncertain underactuated nonlinear systems. The adopted approach is based on sliding mode control and enhanced by a fuzzy scheme to cope with modeling inaccuracies and external disturbances that can arise. The sliding surfaces are defined as a linear combination of both actuated and unactuated variables. A fuzzy inference system is added to compensate the performance drop when, in order to avoid the chattering phenomenon, the sign function is substituted by a saturation function in the conventional sliding mode controller. An application of the proposed scheme is introduced for the cart pole problem, in order to illustrate the controller design method. Numerical results are presented to demonstrate the improved performance of the resulting intelligent controller.