Biped Walking Stabilization on Soft Ground Based on Gait Analysis

This paper describes a walking stabilization control on a soft ground based on gait analysis for a biped humanoid robot. There are many studies on gait analysis on a hard ground, but few physiologists analyze the walking ability of human beings on a soft ground. Therefore, we conducted anthropometric measurement using VICON motion capture system on a soft ground. By analyzing experimental results, we obtained three findings. The first finding is that step height tends to increase to avoid tripping on a soft ground but there are no significant differences in step length and step width. The second finding is that although the CoM amplitude increases in the vertical direction on a soft ground, there are no significant differences in the CoM trajectories in the lateral direction. The last finding is that the head is stabilized during walking not only on a hard ground but also on a soft ground. Based on these findings, we developed a novel walking stabilization control to stabilize the CoM motion in the lateral direction on a soft ground. Verification of the proposed control is conducted through experiments with a human-sized humanoid robot WABIAN-2R. The experimental videos are supplemented.