The Six Hug Commandments: Design and Evaluation of a Human-Sized Hugging Robot with Visual and Haptic Perception

TL;DR

This paper introduces HuggieBot 2.0, a human-sized, soft, warm hugging robot with visual and haptic perception, designed based on six principles to enhance naturalness and user comfort in social touch interactions.

Contribution

It proposes six design tenets for robotic hugging, implements them in HuggieBot 2.0, and empirically evaluates the impact of visual and haptic sensing on user perception.

Findings

HuggieBot 2.0 is more appealing than previous models.

Haptic reactivity significantly improves user perception.

Adding visual and haptic cues enhances the naturalness of robot hugs.

Abstract

Receiving a hug is one of the best ways to feel socially supported, and the lack of social touch can have severe negative effects on an individual's well-being. Based on previous research both within and outside of HRI, we propose six tenets ("commandments") of natural and enjoyable robotic hugging: a hugging robot should be soft, be warm, be human sized, visually perceive its user, adjust its embrace to the user's size and position, and reliably release when the user wants to end the hug. Prior work validated the first two tenets, and the final four are new. We followed all six tenets to create a new robotic platform, HuggieBot 2.0, that has a soft, warm, inflated body (HuggieChest) and uses visual and haptic sensing to deliver closed-loop hugging. We first verified the outward appeal of this platform in comparison to the previous PR2-based HuggieBot 1.0 via an online video-watching study involving 117 users. We then conducted an in-person experiment in which 32 users each exchanged eight hugs with HuggieBot 2.0, experiencing all combinations of visual hug initiation, haptic sizing, and haptic releasing. The results show that adding haptic reactivity definitively improves user perception a hugging robot, largely verifying our four new tenets and illuminating several interesting opportunities for further improvement.