Control of Trajectory Kinematics for Flexible Manipulators Applying Integral Variable Structure Strategy

Abstract

Tracking control of manipulators with joint flexibility is considered to achieve a higher control technique performance. An integral variable structure control (IVSC) approach for robot manipulators is presented for accurate servo-tracking in the presence of load variation, parameter uncertainty and nonlinear dynamic interactions. A procedure is proposed for choosing the control function so that it guarantees the existence of the sliding mode and for determining the coefficients of the switching plane and integral control gain. Furthermore, a modified proper continuous function is introduced to overcome the chattering problem. The proposed (IVSC) approach has been simulated for a two-degree of freedom flexible joint robot, each joint modeled by two-equations of second order. Stability is insured by the use of Liapunov's direct method. The simulation results demonstrate the potential of the proposed scheme. Keywords: Flexible joint robot, Integral variable structure system, Sliding mode, Switching plane, Servo- tracking, Stability criterion, Dynamic uncertainty, Chatter.