Balancing of two wheeled inverted pendulum using SOSMC and validation on LEGO EV3

Abstract

This paper presents Second Order Sliding Mode Controller using Super Twisting algorithm for the two-wheeled inverted pendulum (TWIP). A mathematical model incorporating the dynamics of LEGO EV3 TWIP is considered here. A Sliding Mode Control (SMC) is designed first, then switching surface is synthesized by converting the state space model into regular form. The corresponding system response is plotted, the problem encountered in SMC is that the control input suffers from Chattering. To overcome the drawback a Second Order Sliding Mode Controller (SOSMC) using super twisting algorithm is designed. The contribution of this paper is real time implementation of Super Twisting SOSMC algorithm to balance the lego TWIP in an upright position. The performance and merit of the SOSMC are exemplified by conducting simulations and real-time validation on the LEGO Mindstorms EV3. The issues related to hardware implementation is discussed.