Fuzzy sliding mode control for the two-link robot

Abstract

This paper presents the fuzzy logic combined with the sliding mode (FSMC) to design a robust controller for the two-link robot system. The sliding mode control (SMC) can be used for a nonlinear system with small uncertainties. However, for complex nonlinear systems, the uncertainties are large and produce higher amplitude of chattering due to the higher switching gain. In this work, the nominal model of the robot is assumed known and the fuzzy logic is used to approximate only the unknown dynamic parts of the system, which are incorporated in the so called equivalent control. A small gain robust control term is added to remove the fuzzy approximation error. The simulation results show the effectiveness of the proposed method.