Stair Climbing Stabilization of the HRP-4 Humanoid Robot using Whole-body Admittance Control

TL;DR

This paper presents a novel stabilization method for the HRP-4 humanoid robot to climb stairs, combining whole-body admittance control with quadratic programming-based wrench distribution, demonstrated through real-world experiments.

Contribution

It introduces a combined stabilization approach using admittance control and wrench distribution, enhancing stair climbing performance for humanoid robots.

Findings

Successful stair climbing of 18.5 cm steps by HRP-4

Improved tracking performance with combined control strategies

Open source implementation of the walking controller

Abstract

We consider dynamic stair climbing with the HRP-4 humanoid robot as part of an Airbus manufacturing use-case demonstrator. We share experimental knowledge gathered so as to achieve this task, which HRP-4 had never been challenged to before. In particular, we extend walkingstabilization based on linear inverted pendulum tracking by quadratic programming-based wrench distribution and a whole-body admittance controller that applies both end-effector and CoM strategies. While existing stabilizers tend to use either one or the other, our experience suggests that the combination of these two approaches improves tracking performance. We demonstrate this solution in an on-site experiment where HRP-4 climbs an industrial staircase with 18.5 cm high steps, and release our walking controller as open source software.