An optical external localization system and applications to indoor tracking

Precise robot positioning is important for many applications in indoor environments. Current solutions to the indoor localization problem are either both unreliable and inaccurate, or very expensive. In this paper we propose, design and build a low-cost, robust and accurate indoor localization system using laser light sources. The system calculates the coordinates of a robotic arm by using triangulation algorithms with precisely measured values of the angles of the receiver with respect to the three laser emitters. A system of three rotating lasers and receiver unit was built and deployed in the wing of an aircraft. Using this system, a robotic arm could be localized accurately within error margins defined approximately by Gaussian distributions centered at the objectpsilas true coordinate values and with standard deviations of 0.19 mm, 0.11 mm and 0.34 mm in the x, y and z coordinate directions respectively. The system was also used to detect vertical drop in the robotic arm due to its weight as it extends to perform fitting operations on the skin of the wing. Feedback from the laser localization system was used to adjust the position of the tip of the robotic arm in order to perform a sequence of high precision docking tasks within the aircraft wing.