Autonomous Walking over Obstacles by Means of LRF for Hexapod Robot COMET-IV

This paper presents an autonomous navigation system for a hydraulically driven hexapod robot (COMET-IV) based on point cloud data acquired using a rotating Laser Range Finder (LRF). The size of the robot would prohibit its movement in a stochastic terrain environment if we only consider letting it avoid obstacles. However, the robot has a unique ability to walk over obstacles. We thus proposed the so-called Grid-based Walking Trajectory for Legged Robot (GWTLR) method. The method is developed on the basis of the geometric representation of a stochastic terrain in terms of grid cell characteristics. We also introduced the Grid-cell model for COMET-IV to assess the characteristics of the grid cells and to determine whether each of the cells is traversable or not. Finally, the shortest safe walking trajectory is generated using a search algorithm, A*. The performance of the proposed method is verified by the experimental results of the successful determination of a walking trajectory path and by completely walking over obstacles in various arrangements.