Proceeding of 2018 IEEE International Conference on Current Trends toward Converging Technologies, Coimbatore, India 978-1-5386-3702-9/18/$31.00 © 2017 IEEE 1 MRAC BasedApproachforStabilization of Single Link InvertedPendulum RamashisBanerjee, Department of AppliedPhysics, CalcuttaUniversity ramashisbanerjee@gmail.com Naiwrita Dey Department of AEIE, RCCIIT naiwritadey@gmail.com UjjwalMondal Department of AppliedPhysics, CalcuttaUniversity ujjwalmondal18@gmail.com Abstract—The problem of balancing an inverted pendulum has been a benchmark problem in demonstrating various control design techniques. The principal reasons for it’s popularity are its nonlinear and unstable characteristics. In this paper a single link inverted pendulum system has been chosen and adaptive control algorithm has been implemented for stabilization of the system so that pendulum is always maintained erected in its upright (inverted) position. Model Reference Adaptive Control (MRAC) method is implemented using MIT rule. Minimization of cost function is performed and system response has been observed for different adaption gain. After system modeling the whole process is done in MATLAB Simulink. Keywords—Inverted Pendulum, Adaptive Control, MRAC, MATLAB, Stabilization I. INTRODUCTION Stabilization of an inverted pendulum is considered as an benchmark problem in the field of control system. Many research work has been carried out so far on various effective control methods for inverted pendulum system. In the field of advanced control system adaptive control has gained wide popularity among different control strategies for better performance and accuracy [1].Model Reference Adaptive Control (MRAC) which is a direct adaptive control strategy involves an adjustment mechanism to change the controller parameters. In comparison with the conventional controllers, adaptive controllers perform well for online parameter updation for variation in process dynamics subjected to environmental changes and varying characteristics of disturbances. R.J. Pawar and B.J.Parvat implemented a combination of MRAC and PID control scheme to an inverted pendulum to extend the application of conventional MRAC[2]. K.Suresh in his paper compared the performance analysis of proposed fuzzy MRAC based control for drying process is compared [3]. Suresh B. Pingale compared the application of conventional PID controller with MRAC to an inverted pendulum system. He further implemented fuzzy MRAC which further gave better simulation results [4]. To overcome these problems Priyank Jain and M.J. Nigam deals with designing of controller for second order system with MRAC using MIT rule [5]. MRAC finds wide applications for nonlinear systems. Nonlinear actuator adds variation in process dynamics. MRAC can work for this system[6]. Miaoya Yu and Shigenox Okubo have shown the observability, controllability and stability analysis of a double inverted pendulum model . Inverted pendulums are often used in nonlinear control education and research due to challenging features like unstable and nonlinear dynamics as well as non minimum–phase and non holonomic behavior. MD Shehu presents the dynamic behavior of a nonlinear single link inverted pendulum on cart system based on Lagrange equation[7]. Claudio Malchiorri describes the dynamic model of two degree of freedom manipulator and dynamic equations are obtained [8].This paper is organized as follows: The system dynamics is described very briefly and the transfer function of it is developed. In Section III, a model reference adaptive control scheme design is shown using MIT rule . The proposed method of MRAC adaptive controller is simulated for validation in Section IV, where the dynamic performance of the plant is shown followed by some concluding remarks in Section V. II. SYSTEM MODELLING The physical system considered in this paper is an inverted pendulum which has been shown in Fig.1 Inverted pendulum systems represent a significant class of nonlinear under actuated mechanical systems [9-11] .The system is oriented is this way that a bar is placed vertically . Its pivot point is attached to an angle sensor, encoder for the measurement of the angle and angular velocity . Fig.1. Single inverted pendulum system