Human-like Hesitation Gestures for Human-Robot Resource Conflicts


Human-Robot Interaction, Implicit Interaction, Roboethics, Interactive Human-Robot Communication, Non-verbal Communication, Teamwork and Collaboration


Studies suggest that people feel more positively toward robots that work with people rather than those that replace them. This means that in order to create robots that can collaborate and share tasks with humans, human-human interaction dynamics must be understood – key components of which could be replicated in human-robot interaction.

This research project focused on how simple a non-verbal gesture (like that of jerky hesitant motion of your hand when you and another person reach for the same last piece of chocolate at the same time) can superimposed on the functional reaching motions of a robot, so that robots can express its uncertainty to human users. This research project led to the development of a characteristic motion profile, called the Acceleration-based Hesitation Profile (AHP) a robotic manipulator can use to generate humanlike hesitation motions as a response to resource conflicts (e.g., reaching for the same thing at the same time).

Take a look at how the designed hesitations look in contrast to abrupt collision avoidance responses.
Designed hesitation responses (AHP):

Abrupt stopping responses:

And what happens if the robot doesn’t stop at all:


Moon, A., What Should a Robot Do?: Design and Implementation of Human-like Hesitation Gestures as a Response Mechanism for Human-robot Resource Conflicts, M.A.Sc. thesis, Mechanical Engineering, University of British Columbia, Vancouver, Canada [link]

Related Publication(s):

Moon, A., Parker, C.A.C., Croft, E.A., and Van der Loos, H.F.M., Design and Impact of Hesitation Gestures during Human-Robot Resource Conflicts, Journal of Human-Robot Interaction, 2(3):18-40 [link]

Moon, A., Parker, C.A.C., Croft, E.A., and Van der Loos, H.F.M., Did you see it hesitate? – Empirically Grounded Design of Hesitation Trajectories for Collaborative Robots,IEEE/RSJ International Conference on Intelligent Robots and Systems 2011 [pdf]

Moon, A., Panton, B., Van der Loos, H.F.M., Croft, E.A., Using Hesitation Gestures for Safe and Ethical Human-Robot Interaction, IEEE ICRA’10 Workshop on Interactive Communication for Autonomous Intelligent Robots, Anchorage, United States, May 2010. [pdf]