Effects of Asymmetric Vibration Frequency on Pulling Illusions.

Takeshi Tanabe,Hiroshi Endo,Shuichi Ino

doi:10.3390/s20247086

Abstract

It is known that humans experience a haptic illusion, such as the sensation of being pulled in a particular direction, when asymmetric vibrations are presented. A pulling illusion has been used to provide a force feedback for a virtual reality (VR) system and a pedestrian navigation system, and the asymmetric vibrations can be implemented in any small non-grounded device. However, the design methodology of asymmetric vibration stimuli to induce the pulling illusion has not been fully demonstrated. Although the frequency of the asymmetric vibration is important, findings on the frequency have not been reported. In this study, we clarified the influences of the effects on the pulling illusion based on the investigation of asymmetric vibration frequency differences. Two psychophysical experiments that related to the frequency of asymmetric vibration were performed. Experiment I showed that the illusion occurs for specific vibration waveforms at 40 Hz and 75 Hz. As a result of Experiment II, the threshold was the lowest when the frequency was 40 Hz, and highest when the frequency was 110 Hz. This result supports the previous hypothesis that the Meissner corpuscles and the Ruffini endings contribute to the illusion, while the Pacinian corpuscles do not.

Highlights

Haptic sensation is an important sensory organ for detecting mechanical stimuli applied to the body
The phase differences were calculated from the phases of the fundamental wave and the second harmonic wave after the transformation of the time series data of the asymmetric vibration with the fast Fourier transform (FFT)
As a result of Experiment I, it was shown that the illusion occurred at specific vibration waveforms at 40 Hz and 75 Hz

Summary

Introduction

Haptic sensation is an important sensory organ for detecting mechanical stimuli applied to the body. By artificially presenting information to the haptic sensation, it is possible to induce movements and behaviors. Interfaces that do this are referred to as haptic interfaces. Amemiya et al reported that the illusory force was induced by presenting vibrations with asymmetric acceleration [1]. When asymmetric vibrations are stimulated, the human perceives a rapidly accelerating asymmetric vibration. Asymmetric vibrations at low acceleration values are not perceived since low acceleration values cannot be detected. Amemiya et al demonstrated that users perceive asymmetric vibration stimuli as an illusory pulling force (referred to as a pulling illusion) [1]. The pulling illusion is different from the kinesthetic illusion caused by vibrational stimulation of tendons [5] because the pulling illusion requires stimulation of the fingertips rather

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