Stair Climbing Stabilization of the HRP-4 Humanoid Robot using Whole-body Admittance Control
This paper considers dynamic stair climbing with the HRP-4 humanoid robot as part of an Airbus manufacturing use-case demonstrator. Apart from the fact that HRP-4 had never been challenged to this scenario before, we share experimental knowledge gathered in achieving this task. We also show how walking stabilization based on linear inverted pendulum tracking can be extended with quadratic programming-based wrench distribution and a whole-body admittance controller that relies on both end-effector and CoM strategies. While existing stabilizers tend to use either one or the other of these two approaches, experiments suggest that their combination can improve tracking performance. We demonstrate this solution in a hardware experiment where HRP-4 climbs a staircase with 18.5-cm steps, and release our walking controller as open source software.
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