Emergence of lateral softness sensations in surface tactile tele-presentation systems with force feedback

Abstract

This paper reveals that lateral softness sensations can emerge in surface tactile tele-presentation systems with force feedback, if the systems have improper displacement measurements and/or stiffness mismatches between a fingertip and tactile sensors. In surface tactile tele-presentation systems, friction force should be reproduced on the master device for high fidelity rendering. If, however, the remote tactile sensor is made of soft material to resemble human fingers, users may experience apparent lateral softness, which does not exist in the remote sample. This work investigates such a phenomenon by using a force-reflecting type master-slave system. The phenomenon is analyzed to provide a simple solution to dissolve the lateral stiffness problem. The experiments reveal that the selection of displacement sensing point is important to prevent emergence of the apparent softness, in addition to the matching of sensor stiffness. The paper also discusses how the force reflecting gain affects the phenomenon. © 2014 The Japan Society of Mechanical Engineers.