Force-feedback based Whole-body Stabilizer for Position-Controlled Humanoid Robots

TL;DR

This paper introduces a force-feedback whole-body stabilizer for position-controlled humanoid robots, leveraging six-dimensional force data and dynamics to enhance trajectory tracking performance.

Contribution

It presents a novel stabilizer design that fully exploits force measurements and whole-body dynamics, improving tracking accuracy over existing methods.

Findings

Significant tracking performance improvement in simulations.

Effective stabilization under unknown contact conditions.

Outperforms zero-moment-point based stabilizers.

Abstract

This paper studies stabilizer design for position-controlled humanoid robots. Stabilizers are an essential part for position-controlled humanoids, whose primary objective is to adjust the control input sent to the robot to assist the tracking controller to better follow the planned reference trajectory. To achieve this goal, this paper develops a novel force-feedback based whole-body stabilizer that fully exploits the six-dimensional force measurement information and the whole-body dynamics to improve tracking performance. Relying on rigorous analysis of whole-body dynamics of position-controlled humanoids under unknown contact, the developed stabilizer leverages quadratic-programming based technique that allows cooperative consideration of both the center-of-mass tracking and contact force tracking. The effectiveness of the proposed stabilizer is demonstrated on the UBTECH Walker robot in the MuJoCo simulator. Simulation validations show a significant improvement in various scenarios as compared to commonly adopted stabilizers based on the zero-moment-point feedback and the linear inverted pendulum model.