Self-Guided Lab Lesson to Estimate a Robot's Position Using Distance Sensors

This paper presents a self-guided practical lesson designed for a robotics subject. Students will calculate the position of a robotic arm's end effector as a function of the distances given by three sensors. To do this, an ABB IRB120 robot is used to define the points in space, and also three string potentiometers, the Arduino platform, and the programming language Matlab. With this material, students will design a system that detects the position of the end effector of the robot, to which the ends of three distance sensors will be attached. This document describes the wire-type distance sensors and how to send the data they provide to Matlab making use of an Arduino UNO. Furthermore, a geometrical method named trilateration is introduced to determine the coordinates of a point in 3D. Our results proved the possibility to carry out this self-guided practices in a robotic lab.