Abstract
It is important for autonomous control of a biped robot to obtain the 3D information of the ground on which the robot walks. When a biped robot traverses a floor including slopes, sensors should be able to detect a slope and precisely measure the angle of the slope, along with the positions of its beginning and end. In this paper, we propose a realtime floor sensing method using stereo cameras mounted on a biped robot. We detect a slope in the environment and estimate the inclination angle and the boundary by fitting a set of plane parameter vectors to a two-plane model. For obtaining the parameter vector set, we first determine multiple regions of interest (ROI) in a reference image by using footstep positions up to several steps, scheduled by a current footstep plan. Then the parameter vector of the floor with respect to each ROI are efficiently and accurately estimated by a fast direct method with motion compensation. The fitting result is feedback for stable walking by updating the footstep plan . The validity of the proposed method is demonstrated through online experiments using stereo cameras mounted on the body of a biped robot, Honda ASIMO, traversing a real slope.
