Towards human-robot cooperative object transfer: Perceiving different part of the object during task and motion smoothness

A requirement for human friendly robot had increased dramatically with the demand of assistive robotic technology that having direct interaction with human. One of the examples is the cooperative object transfer performed by two humans. We are aiming at generating a smooth and natural cooperative object transfers performed by a human and robotic system. Prior to the development of such system, the required characteristics for smooth and natural cooperative object transfer between two humans were investigated. Specifically, the required characteristics were on the information exchange experienced between subjects. The effect of observing different part of the object, the availability of motion's directional and time of initiation, and also the effect of object rotational motion towards cooperative motion smoothness between humans are the main issues in this paper. The results indicates that perceiving the Centre part of the experimental object produces more frequent smooth and natural cooperative motion. Also, regardless of Centre or End case, cooperative motion smoothness increase when both direction and time of initiation are available to both subjects. Object rotational motion (mean angular velocity) does not appear to have significant effect on smoothness. The availability of the object's visual information in the planes perpendicular to cooperative task execution should be considered for smooth motion. Thus, for generating smooth and natural human and robot cooperative motion, the aforementioned characteristics should be made available.