Localization Performance of Multiple Vibrotactile Cues on Both Arms

Abstract

To present information using vibrotactile stimuli in wearable devices, it is fundamental to understand human performance of localizing vibrotactile cues across the skin surface. In this paper, we studied human ability to identify locations of multiple vibrotactile cues activated simultaneously on both arms. Two haptic bands were mounted in proximity to the elbow and shoulder joints on each arm, and two vibrotactile motors were mounted on each band to provide vibration cues to the dorsal and palmar side of the arm. The localization performance under four conditions were compared, with the number of the simultaneously activated cues varying from one to four in each condition. Experimental results illustrate that the rate of correct localization decreases linearly with the increase in the number of activated cues. It was 27.8 percent for three activated cues, and became even lower for four activated cues. An analysis of the correct rate and error patterns show that the layout of vibrotactile cues can have significant effects on the localization performance of multiple vibrotactile cues. These findings might provide guidelines for using vibrotactile cues to guide the simultaneous motion of multiple joints on both arms.

Temporal Asynchrony but Not Total Energy Nor Duration Improves the Judgment of Numerosity in Electrotactile Stimulation

“…The main finding of our study is that the sequential stimulation elicited a significantly higher accuracy in judging the number of activated electrodes compared to the simultaneous and intermittent condition. The general trend in all conditions was toward an underestimation of the number of activated channels, i.e., the perceived number of active channels was mostly three when more than three channels were actually active in the simultaneous and intermittent conditions, confirming the results of previous studies (Gallace et al, 2006;Riggs et al, 2006;Wang et al, 2018). However, this underestimation was significantly lower in the sequential condition.…”

“…Several studies have demonstrated that subject's ability to process multiple tactile stimuli delivered over the body surface, or even across the fingertips, is limited. That is, people are simply unable to enumerate accurately more than two or three tactile stimuli applied simultaneously (Gallace et al, 2006(Gallace et al, , 2008Riggs et al, 2006;Wang et al, 2018). The human accuracy in tactile enumeration tasks decreased as the number of tactors activated increased.…”

Non-informative vision improves spatial tactile discrimination on the shoulder but does not influence detection sensitivity

“…To do so, we make the assumption that increasing the numerosity of tactile stimuli makes the numerosity judgment more difficult. This assumption is well supported by previous findings showing that the underestimation of the number of stimuli increases with the number of tactile stimuli (Gallace et al 2006(Gallace et al , 2007Wang et al 2018).…”

Toward Sustainable Haptics: A Wearable Vibrotactile Solar‐Powered System with Biodegradable Components

“…However, it has been demonstrated that the stimuli localization accuracy decreases with the increase in the number of activated cues. [77,78] Therefore, this implementation only transmits feedback from one Eco-Tac at a time to maximize the user capacity to distinguish signals coming from different devices and thus different guidance directions.…”