Vibrotactile Stimulation to Increase and Decrease Texture Roughness

We have developed a texture display system that modifies the perceived roughness of textured surfaces via a voice coil actuator worn on the finger. To increase the roughness sensations, the vibrotactile stimuli from the actuator simulate the skin deformations that are activated when a wavy surface is scanned. Conversely, to decrease the roughness sensations of the textured surface, a high-frequency vibrotactile stimulus offsets the activity levels of tactile mechanoreceptors. This offset suppresses the perceived roughness of the surfaces being touched, with increase in the offset correlating with increase in the feeling of smoothness of the surfaces. We conducted an experiment in which we tested the effects of these two types of vibrotactile stimulation on grating roughness specimens, with subjective responses acquired from eight participants via the magnitude estimation method. The results obtained indicate that our method selectively increases and decreases the roughness felt. The intention is for the technique to be used to develop an augmented reality device for textures.