Physical and behavioral comparison of haptic touchscreens quality

TL;DR

This paper introduces an objective evaluation method for haptic touchscreen quality, combining physical measurements and user-based metrics to compare different friction modulation technologies.

Contribution

It proposes a standardized framework for assessing haptic feedback performance, addressing the lack of existing metrics and enabling device benchmarking.

Findings

Ultrasonic and electroadhesion haptic devices were compared.

The method successfully distinguished device performance based on physical and user metrics.

Results support the development of standard benchmarks for haptic touchscreen quality.

Abstract

Touchscreens equipped with friction modulation can provide rich tactile feedback to their users. To date, there are no standard metrics to properly quantify the benefit brought by haptic feedback.The definition of such metrics is not straightforward since friction modulation technologies can be achieved by either ultrasonic waves or with electroadhesion. In addition, the output depends strongly on the user, both because of the mechanical behavior of the fingertip and personal tactile somatosensory capabilities. This paper proposes a method to evaluate and compare the performance of haptic tablets on an objective scale. The method first defines multiple metrics using physical measurements of friction and latency. The comparison is completed with metrics derived from information theory and based on pointing tasks performed by users. We evaluated the comparison method with two haptic devices, one based on ultrasonic friction modulation and the other based on electroadhesion. This work paves the way toward the definitions of standard specifications for haptic tablets, to establish benchmarks and guidelines for improving surface haptic devices.