A QR Code-based High-Precision Docking System for Mobile Robots Exhibiting Submillimeter Accuracy

This paper presents a high-precision docking system enabling controlled motion of mobile robots and automatic guided vehicles in micrometer range. The developed system employs a low-cost, vehicle installed camera and a docking base with Quick Response (QR) codes in the form of a two-dimensional matrix. The docking base is free of active components, eliminating the need for maintenance, and minimizing manufacturing or installation costs. A robust localization algorithm is developed that provides real-time position feedback at 60 Hz with submillimeter accuracy. Redundancy is established by calculating the vehicle’s pose using multiple QR codes; thus, if one or more QR codes are damaged, the feedback stays unaffected. By design, the system is insusceptible to light variance. Using a prototype robotic platform, excellent mean absolute errors of $39 \mu \mathrm{m}$ in position, and 8.8 millidegrees in orientation are achieved, providing experimental validation of the docking system.