Incorporating Sliding Mode and Fuzzy Controller with Bounded Torques for Set-Point Tracking of Robot Manipulators

Abstract

In this paper, an incorporating sliding mode and fuzzy controller is designed for set-point tracking of robot manipulators with friction and restriction on input torque magnitude due to saturation of actuators. Sliding mode control (SMC) has fast response and is robust to uncertainties and disturbances, but it suffers from chattering problem, in addition, its performance is decreased by prescribing limits on control input. On the other hand, the fuzzy control which is used here has very small tracking error but its response is slower than SMC case. Therefore, in order to profit from both merit of these controllers, at first, the sliding mode controller constraints the states to reach sliding surface. When the tracking error would be less than predefined value, then the fuzzy controller is responsible for control action. Comparative simulation results demonstrate the efficiency of this combination.