Md. Akhtaruzzaman and Amir A. Shafie
Inverted pendulum control is one of the fundamental problems in the field of control theory especially in the control of a walking robot. This paper describes the steps to design various controllers for a rotary motion inverted pendulum which was operated by a rotary servo plant, SRV 02 Series. The paper then compares the classical and modern control techniques used to design the control systems. Firstly, the most popular system, Single Input Single Output (SISO) system, was applied where 2DOF Proportional-Integral-Derivative (PID) compensator design was included. In this paper the common Root Locus Method is described step by step to design the two compensators of PID controller. Designing the control system using 2DOF PID is quiet challenging task for the rotary inverted pendulum because of its highly nonlinear and open-loop unstable characteristics. Secondly, the paper describes the two Modern Control techniques that include Full State Feedback (FSF) and Linear Quadratic Regulator (LQR). For the experiment, FSF and LQR control systems were tested both for the Upright and Swing-Up mode of the Pendulum. Finally, experimental and MATLAB based simulation results are described and compared based on the three control strategy which were designed to control the Rotary Inverted Pendulum. Both the simulated and experimental results show that the LQR controller presents better performance over the other two controllers.
