Making a three-dimensional map in complicated environment by using a bridge inspection robot with a laser range finder

Abstract

Many infrastructures such as bridges and tunnels had been constructed in various parts of Japan during the high economic growth period. They need periodic inspection because they are aging. Inspecting them by inspector is both costly and time-consuming. There is a strong demand for practical bridge inspection robots to reduce the costs and times. The inspection robot running autonomously on the bridge needs to determine moving route and to estimate self-position. The robot must have a three dimensional map of the bridge to take these actions. This paper proposes a method of making a three-dimensional occupancy grid map of the large scale infrastructure where the inspector cannot go easily such as an underside of the bridge. A bridge inspection robot equipped with magnets had been developed in present study. We attached a measuring device which consists of a small 2D laser range finder and a servo motor. Experiments were conducted to make the 3D map by using the robot. The robot climbed to target position on the wall without falling although it was equipped with the measuring device which is heavy. Moreover, the robot can make the 3D occupancy grid map and the map can be useful to inspect bridges.