Presenting Human-Robot Relative Hand Position using a Multi-Step Vibrotactile Stimulus for Handover Task

Abstract

For humans to hand over an object to a robot, confirming the robot hand's position through their sensory organs (i.e., vision) is required. Only then can perform the hand-reaching task. This step is time-consuming and visual demand can also degrade other simultaneously conducted tasks performances. We assume that eliminating this step can lead to a rapid and precise reaching task. We propose a method to directly present the relative position of human-robot hands using phantom sensation-based vibrotactile stimulus on the human reaching arm. A multi-step vibrotactile cue; 1) gross motion, 2) fine motion, and 3) deadband, is provided to indicate the direction, distance to the target, and a signal indicating the reached target, respectively. The experimental result shows that users could precisely recognize the target position in a given shorter time. This indicates that humans can use the proposed method to initiate their ballistic movement for hand-reaching during the handover task.