Module for Monitoring the Probe-Skin Contact Force in the Study of Vibration Perception on the Wrist.

Dorota Czopek,Jerzy Wiciak,Robert Barański

doi:10.3390/s21062128

Abstract

This paper presents a module for monitoring the contact force between a probe for measuring vibration perception on the wrist and the skin. The module was designed for an original measuring stand for the automatic testing of the vibrotactile discrimination thresholds using the psychophysical adaptive method of 1 up–2 down with two or three interval forced choices (2IFC, 3IFC). Measurement methods were implemented in LabVIEW software. The inspiration for the project was the need to check the possibility of building a vibrating interface for transmitting information through vibrations delivered to the wrist via a bracelet. The test procedure on the wrist is not standardized; however, during its development, the recommendations of the Polish Norm–International Organization for Standardization PN-ISO 13091-1, 2006 were adopted. This standard contains methods for measuring vibration sensation thresholds on the fingertips for the assessment of neural dysfunction. The key to the repeatability of measurements seems to be the ability to continuously control the pressure of the measuring probe on the skin. This article compares two solutions for measuring the contact force along with an analysis of their accuracy and the impact of vibrations on the measured values. Moreover, the results of measurements of vibrotactile amplitude and frequency discrimination thresholds obtained on the ventral wrist at five frequencies (25, 32, 63, 125 and 250 Hz) are presented.

Highlights

In recent years, research related to haptic perception has been performed because of the development of techniques for augmented and virtual reality, including telepresence in military contexts and telemedicine
Haptic devices allow people to obtain a sense of touch with the virtual environment generated by a computer
Many conferences are being conducted on this subject because despite the existence of considerable knowledge, there remains much to be researched in this field; to this end, the WHC World Haptics Conference is held every two years [3]

Summary

Introduction

Research related to haptic perception has been performed because of the development of techniques for augmented and virtual reality, including telepresence in military contexts and telemedicine. Haptic devices allow people to obtain a sense of touch with the virtual environment generated by a computer. By applying forces, vibrations, or motions to the user, haptic devices aid in the remote control of virtual objects and enable deeper immersion in computer-generated reality [1,2]. The described research was inspired by the design of a vibrating bracelet for blind and partially sighted people, in line with the idea of a smart city for all. It was decided that the information must be conveyed by means of non-acoustic signals because the perception of the natural sounds of the environment is an important element in the spatial orientation of blind people. After analyzing the possibilities, based on a questionnaire and interviews with the target

Methods

Results

Conclusion