Feasibility: Can Humanoid Robots Overcome Given Obstacles?

The wide and potential applications of humanoid robots require that the robots can walk in complex environments cluttered with various obstacles. In such environments, the robots often need to overcome obstacles by stepping-over, stepping-on/down, or stepping-around. Before the implementation, it must be made sure whether the robots can do so, which is the so-called feasibility. In this paper, we give a more thorough feasibility analysis and more practical results of stepping-over and stepping-on/down, by extending our previous analyses in 2-D case to 3-D motion of the robot. Considering the geometry of the obstacle, the shapes and sizes, and kinematics of the robot legs, we use optimization technique to build corresponding models with nonlinear constraints (including those on collision avoidance and robot balance) to find the maximum height of the obstacle that the robot can step over or on/down. The results can be used as a prior knowledge and a database for motion planning of obstacle overcoming. The feasibility also provides an approach for evaluating the humanoid capability of obstacle overcoming.