Trajectory Generation for Biped Robot Walking on Hill with Changing Slope

Abstract

This paper proposes a trajectory generation method for a biped robot to walk on an inclined surface. In order to generate the walking trajectory, the robot is modeled as one particle and the momentum equation with respect to its zero moment point is used. A few additional assumptions are used to generate the walking trajectory. First, the center of mass moves in parallel with the slope of the surface. Second, the zero moment point of the robot should be fixed at the supporting foot during a single support phase and moves from the previous supporting foot to the next supporting foot during a double support phase. When the slop of the surface changes while the robot walks, walking conditions of the robot are also changed, and two piece-wise continuous trajectories are joined smoothly during the double support phase at the slop change. The effectiveness of the proposed trajectory generation method was proved in simulations.