PSO-Super Twisting SMC for Balancing the TWIP using LEGO EV3 Model

This paper presents a PSO-based tanh super twisting sliding mode controller (PSO-STSMC) for the balancing of two-wheeled inverted pendulum (TWIP). Here, a mathematical model that incorporates the dynamics of the LEGO EV3 TWIP is taken into consideration. A Sliding Mode Control (SMC) is designed initially, and then the switching surface is synthesized by converting the state space model into standard form. Then the pole placement technique is used to determine the sliding surface constants. Then the corresponding system response is plotted. The primary drawback of SMC is that the control input has Chattering. A PSO-based tanh super-twisting sliding mode controller is designed to overcome the Chattering in control input. The discontinuous control input in the conventional SMC is replaced by a smooth continuous approximation, i.e., the tanh function. Furthermore, the optimal sliding surface gains are obtained from the particle swarm optimization technique. This study aims to design the PSO-based tanh super-twisting sliding mode controller to balance the lego TWIP in an upright position. The proposed controller minimizes the Chattering in control input, improves the settling time, and gives high robustness to disturbance and parametric variations. The performance and merit of proposed controller with respect to conventional SMC are exemplified by conducting simulations in MATlab.