Investigating Non-Verbal Cues in Cluttered Environments: Insights Into Legible Motion From Interpersonal Interaction

Melanie Schmidt-Wolf, Tyler J. Becker, Denielle Oliva, Monica N. Nicolescu, David Feil-Seifer

Abstract: In human-robot collaboration, legible intent of the robot is critical to success as it enables the human to more effectively work with and around the robot. Environments where humans and robots collaborate are widely varied and in the real world are most often cluttered. However, prior work in legible motion utilizes primarily environments which are uncluttered. Success in these environments does not necessarily guarantee success in more cluttered environments. Furthermore, the prior work has been primarily performed based on results from robot-human studies and the problem has not been studied from the prospective of what people do to express intent to each other. Therefore, this work addresses a gap in current research into legible robot arm motion in the following ways: first we perform a human-human study in order to establish the factors which humans use to express their intent through body language, and second we perform the study in a cluttered and varied environment. Through the study we showed that the primary factors which people considered are: timing, kinematic parameters, hand gestures, object proximity, etc. The results also showed that legibility is correlated with perceived safety, perceived social intelligence, the collaborator’s contribution, and trust which further speaks to the importance of legible motion. Future work will utilize the pose data extracted from the study’s video recordings to develop a model for legible motion.