Tactile perception of change in friction on an ultrasonically actuated glass surface

Abstract

We conducted psychophysical experiments to investigate human haptic perception when they experience a step change in friction on an ultrasonically actuated glass surface under two experimental conditions; sliding finger and stationary finger pressed on the surface. During the experiments, the forces acting on the subjects' finger and the out of plane vibrations of the touch surface were measured by a force and a piezoelectric sensor, respectively. The results showed that stationary finger more easily detected falling friction, whereas, sliding finger was more sensitive to rising friction at higher actuation levels. Moreover, sliding finger was twice more sensitive to changes in friction than stationary finger. Finally, we found that the rate of change of contact forces were best correlated with the subjects' perception of change in friction under both experimental conditions.