Mobile robot for marking free access floors at construction sites

Abstract

Improving of the productivity of construction work is an urgent task, because the shortage of construction workers in Japan has become a major social issue. Marking work for building materials that is currently performed manually is an indispensable part of the construction process. Its possible automation would allow construction workers to focus on the installation step and thus significantly boost their productivity. In this study an automated mobile robotic system for marking free access floors has been developed. Building such floors requires drawing grid-pattern lines whose intersections (representing the positions of future pedestal bases) can be automatically marked by the proposed system consisting of a mobile robot with a marking device at its center and a laser positioning unit. Cross marks are drawn on the floor by controlling the marking device, while the laser positioning unit accurately moves a line laser along a designated direction and measures the distance to a projected object. The marking robot tracks the line laser and arrives at a designated point. The deviation between the designated position and the robot center is calculated, and the cross mark is drawn exactly at the former location. The marking performance of the developed robotic system has been evaluated by conducting an experiments inside a 6 m × 6.5 m area at a construction site. It is found that the average deviation between the marked and designated positions is 2.3 mm, while 77% of all deviations are smaller than 3 mm.