Pivot Turning Measurement of Relative Position and Posture for Moving Robots System Using Stereo-Camera

Abstract

The stereo-camera method is used to measure the positions of robots. In taking the measurements it is important to precisely measure the distance between cameras and the relative posture of the cameras. Therefore, we developed a novel method for measuring a mobile robot's relative position and posture by photographing robots’ pivot turns. A mobile robot system was equipped with a camera and an identification marker that made it possible to measure position and posture with the stereo-camera method when the viewpoint changed freely. One robot photographs the pivot turns of another. As the latter turns, an identification marker on it is used to trace the movement onto an image. The turning robot’s position and posture is determined by the length and angle of the trace. This procedure makes it possible for each of the two robots to obtain their relative position and posture, making the measurement of the stereo-camera method precise. Measuring with a fixed stereo camera is impossible when there are obstacles in the environment and the object being measured moves over a wide range. However, this robot system was able to use the stereo-camera method to expand the measurement range.