Real-time Human Progress Estimation with Online Dynamic Time Warping for Collaborative Robotics

Davide De Lazzari^1,2*Matteo Terreran¹Giulio Giacomuzzo¹Siddarth Jain²Pietro Falco¹Ruggero Carli¹Stefano Ghidoni¹Diego Romeres^2*

• ¹University of Padua, Padua, Italy
• ²Mitsubishi Electric Research Laboratories, Cambridge, MA, United States

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.