The Power of Combined Modalities in Interactive Robot Learning
Helen Beierling, Anna-Lisa Vollmer
TL;DR
The paper addresses how to teach robots through human-in-the-loop feedback by combining multiple feedback modalities. It uses probabilistic movement primitives ($ProMP$) to represent trajectories and the PIBB$^2$ algorithm to learn a distribution over $ProMP$ weights from multimodal feedback, including six meta-modalities: Guidance, Correction, Demonstrations, Exploration, Speed, and Fallback. In a minigolf task with a Kinova robot, a two-group study shows that combining modalities improves learning performance and user satisfaction, with Group 2 achieving more hits and higher SUS scores (e.g., first hit after $17.56$ vs $34.60$ attempts; $p=0.0007$ for total hits). The results indicate that Guidance and Speed are most valued, while Exploration requires clearer semantics to consistently aid learning, underscoring the practical benefits and design considerations for multimodal interactive robot learning.
Abstract
This study contributes to the evolving field of robot learning in interaction with humans, examining the impact of diverse input modalities on learning outcomes. It introduces the concept of "meta-modalities" which encapsulate additional forms of feedback beyond the traditional preference and scalar feedback mechanisms. Unlike prior research that focused on individual meta-modalities, this work evaluates their combined effect on learning outcomes. Through a study with human participants, we explore user preferences for these modalities and their impact on robot learning performance. Our findings reveal that while individual modalities are perceived differently, their combination significantly improves learning behavior and usability. This research not only provides valuable insights into the optimization of human-robot interactive task learning but also opens new avenues for enhancing the interactive freedom and scaffolding capabilities provided to users in such settings.
