Biped walking on a low friction floor

Biped walking on a low friction floor is analyzed in this paper. For a given walking pattern, we can calculate a necessary friction coefficient which allows the robot to perform the expected motion. To reduce the maximum necessary friction coefficient, a pattern generation based on preview control theory is explained. We also describe a calculation of slip concerned ZMP, which provides a good prediction of falling caused by slips. Finally, we test a walk of 135 [km/h] on low friction environment using a humanoid robot HRP-2. The robot could successfully walk over the slippery area whose friction coefficient is 0.14.