AUTHOR=De Lazzari Davide , Terreran Matteo , Giacomuzzo Giulio , Jain Siddarth , Falco Pietro , Carli Ruggero , Ghidoni Stefano , Romeres Diego 

TITLE=Real-time human progress estimation with online dynamic time warping for collaborative robotics

JOURNAL=Frontiers in Robotics and AI

VOLUME=Volume 12 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/robotics-and-ai/articles/10.3389/frobt.2025.1623884

DOI=10.3389/frobt.2025.1623884

ISSN=2296-9144

ABSTRACT=Real-time estimation of human action progress is critical for seamless human-robot collaboration yet remains underexplored. With this paper we propose the first real-time application of Open-end Soft-DTW (OS-DTWEU) and introduce OS-DTWWP, a novel DTW variant that integrates a Windowed-Pearson distance to effectively capture local correlations. This method is embedded in our Proactive Assistance through action-Completion Estimation (PACE) framework, which leverages reinforcement learning to synchronize robotic assistance with human actions by estimating action completion percentages. Experiments on a chair assembly task demonstrate OS-DTWWP’s superiority in capturing local motion patterns and OS-DTWEU’s efficacy in tasks presenting consistent absolute positions. Moreover we validate the PACE framework through user studies involving 12 participants, showing significant improvements in interaction fluency, reduced waiting times, and positive user feedback compared to traditional methods.