Design and fabrication of a two wheels self-balancing robot for automatic control education

Abstract

This article describes the design and fabrication of a Two Wheels Self-Balancing Robot (TWSBR) which allows to high school and graduate students in areas related to dynamical systems and control, to implement control laws in an open-source platform. Currently there are many professional or commercial platforms whose maintenance and cost are high. For this reason, the development of an TWSBR is proposed, that allows experimentation on typical control topics. A typical architecture of an TWSBR, makes use of: (i) one gyroscope with accelerometer to measure the tilt angle of the robot, (ii) two optical encoders to measure the angular position and velocity of the wheels and (iii) a microcontroller to perform the control law. It is important to remark that the TWSBR architecture proposed in this work, utilizes two stepper motors and power drivers in micro stepping mode, letting to reach a resolution of, 0.225° per step, besides of low electrical noise, in comparison with the optical encoders and DC motors used in other prototypes. This better resolution helps to obtain a better TWSBR response and provides greater flexibility for the implementation of new control laws. Finally, it is important to say that the experimental results show a proper functioning of the prototype.