Optimization of Human Tactile Sensation Using Stochastic Resonance

Abstract

The development of tactile sensors and its data processing are crucial to advance robotics for allowing robots to explore and handle objects. Robots must sense the tactile feelings caused by contact between their hands and a human. This paper presents an influence of the stochastic resonance (SR) on tactile sensation that can enhance sensitivity by superimposing proper noise upon otherwise undetectable weak signals to detect the target signals. To investigate the SR of human tactile sensation and elucidate the mechanism of tactile SR, we performed a sequence of psychophysical experiments applying tangential directional vibration with a size of 2.5 mm and 8 mm stimulus point. We examined the difference threshold (DL) variation obtained from these experiments to clarify which condition of vibration direction and stimulus size causes the strongest SR. Furthermore we compared these results of tangential stimulus with results of normal stimulus obtained from our prior study. The experimental results show that neither normal nor tangential DL is significantly affected by stimulus point size. Moreover, tactile sensing precision is enhanced by appropriate noise and the characteristics of SR with tangential stimulation are quite different from those with normal stimulation.