Control of Tactile Surface-Roughness Sensation Using Ultrasonic Vibration

A method is proposed for controlling tactile sensation of surface roughness. The finger tracing a surface is acted upon by an upward floating force, which is called 'squeeze force' by applying ultrasonic vibration with a few micrometers amplitude to the surface. The sensation thus becomes smoother. By controlling the vibration amplitude, the sensation of the surface can be controlled from the initial 'rough' to 'smooth' without altering the actual surface profile. Experiments using five to ten subjects showed the properties of the proposed method, such as the effect of ultrasonic vibration on tactile sensation, the positive relationship between the generation of a smooth feeling and vibration amplitude, and the dependence on vibration frequency. A model of the tactile control mechanism, which focuses on the reduction of friction, is also simulated. The results qualitatively agreed well with our experimental results.