Human Tactile Stochastic Resonance Affected by Stimulus Direction

Abstract

Tactile sensors and their data processing are very important in enabling robots to handle objects. With information processing by biological organisms, stochastic resonance (SR) can enhance sensitivity by superimposing proper noise upon undetectable weak signals to detect the target signal. To investigate the SR of human tactile sensation and elucidate the mechanism of tactile SR for the development of a new tactile sensor, we performed a series of psychophysical experiments using tangential vibration with 2.5‐mm and 8‐mm‐sized stimulus points. We examined the difference threshold (difference limen; DL) variation obtained from these experiments to clarify which conditions of vibration direction and stimulus size cause the strongest SR. 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. The characteristics of SR, with normal vibration obtained from our prior study is quite different from that with tangential vibration

Stochastic Resonance in a Simple Threshold Sensor System with Alpha Stable Noise

“…For Cauchy noise, we have analytically derived the nonlinear relation among the optimal deviation parameter, the threshold and the input signal amplitude, while for general alpha stable noise, we have found that SR in the simple sensor system can occur for any alpha stable index, but the resonant effect weakens as the alpha stable index decreases or the skewness parameter increases. Even if this weakening effect is just the same as that observed for bistable ensembles [12] or oscillators, [20] the investigation should have importance in weak signal detection, low-contrast image restoration, and biomedical engineering because of the particularity about the threshold systems. In the near future, we will explore the effect of alpha stable noise on SR in the threshold sensor arrays and multi-threshold sensor systems.…”

“…[9−12] For example, Liu et al discussed sensor fusion enhancement via optimized SR at local sensors, [10] Lin et al investigated the synergetic effect in multi-sensor coupled stochastic resonator system, [11] and Beceren et al performed psychophysical experiments in studying the human tactile SR affected by stimulus direction. [12] Nevertheless, nearly all of these investigations in this regard are concentrating on normal diffusion, where Gaussian noise is used to model the environmental fluctuation. Note that anomalous diffusion with heavy-tailed non-Gaussian distribution is universal in nature [5−7,13−14] and thus it is necessary to explore the effect of non-Gaussian noise on SR in threshold sensor systems.…”

Fine Texture Detection Based on a Solid–Liquid Composite Flexible Tactile Sensor Array

“…The stochastic resonance algorithm (SR, hereafter) is a commonly used weak signal detecting method, which adds random noise to the weak signal to improve the detectability of the target signal or enhance the accuracy of information interpretation [ 24 ]. Through a series of psychophysical experiments, Kadir Beceren et al [ 25 , 26 ] proved that SR could affect the difference threshold of human tactile sensation, and appropriate noise can enhance the accuracy of tactile sensing. Yuichi Kurita et al [ 27 ] used the SR to develop surgical forceps with sensorimotor-enhancing capabilities and verified its texture detection capability, which was of great help to surgeons in laparoscopic surgery.…”

Investigation of Human Tactile Stochastic Resonance Depending on Frequency Effect

“…So far, it has been found that there are four kinds of mechanoreceptive units in human skin: the fast adaptive type I unit (FA-I), fast adaptive type II unit (FA-II), slowly adaptive type I unit (SA-I), and slowly adaptive type II unit (SA-II). Basic characteristics of mechanoreceptive units have been reviewed in our previous paper [24]. Miyaoka et al…”

“…So far, it has been found that there are four kinds of mechanoreceptive units in Based on the previous studies, we investigated the influence of the SR phenomenon on human tactile sensation to elucidate the mechanism of SR. Our previous works [24] [25] show that tactile sensing precision is enhanced by proper noise; also, neither normal nor tangential difference threshold is significantly affected by stimulus point size in the low frequency condition.…”