Free-Chattering Fuzzy Sliding Mode Control of Robot Manipulators with Joints Flexibility in Presence of Matched and Mismatched Uncertainties in Model Dynamic and Actuators

Abstract

In this paper, a simple but effective voltage-based fuzzy sliding mode control (SMC) is proposed to control the position of a class of flexible-joints robot manipulators with n degrees of freedom in presence of matched and mismatched uncertainties related to the electrical and mechanical equations. In order to solve problems in comparison with conventional SMC, a sliding surface with the time-varying parameter is proposed which not only eliminates chattering and increases the stability of the closed loop system, but also prevents the increase of the control input voltage. Furthermore, an approach is proposed to calculate the sliding surface vector coefficients which, in presence of the existing uncertainties, guarantee the global asymptotically stability of the closed loop system. Finally, simulation and practical implementation results are presented to exhibit the helpfulness of the proposed control technique compared to the previous methods.