Online design of torso height trajectories for walking patterns that takes future kinematic limits into consideration

This paper presents an online generation method of a torso height trajectory as a part of walking pattern generation. Torso height trajectories should be designed carefully in order to meet the constraints that are given by the existence of the inverse kinematics solution and limitations of the leg joint angle velocity. Limitations of the height in the future are evaluated and taken into consideration for deciding the height of the torso at a moment. In this manner a trajectory that satisfies the limitations and given maximum acceleration and velocity is generated. The proposed method is implemented as a part of online walking control system of full-size Humanoid HRP-2. Its performance is confirmed through the pattern generation in the walking control system.