A Smart Wheelchair (SW) is an electric powered wheelchair, equipped with sensors and computational capabilities, with the general aim of both enhancing independence and improving perceived quality of life of the impaired people using it. SWs belong to the class of semi-autonomous mobile robots, designed to carry the user from one location to another of his/her choice. For such systems, the localization aspect is of utmost concern, since GPS signal is not available indoors and alternative sensor sets are required. This paper proposes a low- cost artificial landmark-based localization system for mobile robots operating indoor. It is based on Quick Response (QR) codes, which contain the absolute position of the landmark: a vision system recognizes the codes, estimates the relative position of the robot (i.e., displacement and orientation) w.r.t. the codes and, finally, calculates the absolute position of the robot by exploiting the information contained in the codes. The system has been experimentally validated for self-localization of a smart wheelchair, and experimental results confirm that navigation is possible when considering an high QR-code density, while QR-code low density conditions permit to reset the cumulative odometry error.
A QR-code localization system for mobile robots: Application to smart wheelchairs / Cavanini, Luca; Cimini, Gionata; Ferracuti, Francesco; Freddi, Alessandro; Ippoliti, Gianluca; Monteriu, Andrea; Verdini, Federica. - ELETTRONICO. - (2017), pp. 1-6. (Intervento presentato al convegno European Conference on Mobile Robots (ECMR) tenutosi a Paris, France nel 6-8 Sept. 2017) [10.1109/ECMR.2017.8098667].