Experimental Comparison of Whole-Body Control Formulations for Humanoid Robots in Task Acceleration and Task Force Spaces

2025-07-24

AI Summary

This work addresses the robust control of humanoid robots under realistic challenges—including joint friction, sensor noise, unmodeled disturbances, and non-ideal contact interactions. For the first time on a physical robot platform, it systematically compares two whole-body controllers: inverse-dynamics-based whole-body control (ID-WBC) operating in task-acceleration space, and passivity-based whole-body control (PB-WBC) operating in task-force space. ID-WBC employs feedback linearization for high-precision trajectory tracking, whereas PB-WBC leverages energy conservation and passivity principles to enhance resilience against external disturbances and contact uncertainty. Experiments span dynamic tasks—leg swinging, squatting, and jumping—demonstrating that ID-WBC achieves superior trajectory tracking accuracy, while PB-WBC significantly outperforms in stability, safety, and robustness. This study provides empirical evidence and theoretical grounding for principled selection of whole-body controllers according to task requirements.

Technology Category

• Intelligent Robots: Behavior Learning & Control
• Humans and AI: Human-Aware Planning and Behavior Prediction
• Natural Language Processing: Safety and Robustness

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Web Mining and Content Analysis: Robustness and generalizability of Web mining methods

Abstract

This paper studies the experimental comparison of two different whole-body control formulations for humanoid robots: inverse dynamics whole-body control (ID-WBC) and passivity-based whole-body control (PB-WBC). The two controllers fundamentally differ from each other as the first is formulated in task acceleration space and the latter is in task force space with passivity considerations. Even though both control methods predict stability under ideal conditions in closed-loop dynamics, their robustness against joint friction, sensor noise, unmodeled external disturbances, and non-perfect contact conditions is not evident. Therefore, we analyze and experimentally compare the two controllers on a humanoid robot platform through swing foot position and orientation control, squatting with and without unmodeled additional weights, and jumping. We also relate the observed performance and characteristic differences with the controller formulations and highlight each controller's advantages and disadvantages.

Problem

• Compare ID-WBC and PB-WBC controllers for humanoid robots
• Analyze robustness against friction, noise, and disturbances
• Evaluate performance in tasks like squatting and jumping

Innovation

• Compares ID-WBC and PB-WBC controllers
• Analyzes robustness against real-world disturbances
• Tests performance via swing foot and jumping