Design, implementation and real-time digital control of a cart-mounted inverted pendulum using Atmel AVR Microcontroller

Abstract:- The paradigmatic inverted pendulum problem is one of the most important and favorite topics for Control System enthusiasts. A solution to this inherently unstable problem is discussed in this paper, with the pendulum being cart-mounted and the cart itself being moved by a belt spread between two pulleys. The pendulum is constrained to swing within predefined limits of ±25 degrees on either side of vertical axis. The feedback signals are cart and the pendulum positions using optical encoders. The digital control of the system is developed using an Atmel MEGA (ATMEGA) 8535 microcontroller. The user can tune the parameters of the system through a user interface provided in the form of a keypad and a Liquid Crystal Display (LCD). Mechanical aspects of the apparatus, electronic circuitry, control technique and experimental results are elaborated upon in the paper. The apparatus is intended to be used as a general purpose Control Systems lab trainer to teach the characteristics of Proportional (P), Integral (I), Derivative (D), PI, PD and PID controls to electrical engineering students. Intuitive reasoning and an insightful approach to the control design are major emphasis of this effort