Effect of external vehicle perturbations on tactile perception by electrovibration

Abstract

Navigating touchscreens in vehicles becomes increasingly challenging when subjected to external perturbations like air turbulence or bumpy roads. These perturbations can lead to a loss in task performance, reduced finger accuracy, and increased frustration among users. To address these issues, electrovibration has emerged as a promising technology to enhance touchscreen interactions by providing users with better feedback and maintaining touch stability even under challenging conditions. Before we investigate if electrovibration helps users in challenging conditions, first the effects of external perturbations on tactile perception by electrovibration must be found. To investigate the impact of external perturbations on electrovibration perception, we conducted psychophysical experiments with 18 participants interacting with an electrostatic display mounted on the cockpit of the SIMONA flight simulator. We measured participants’ absolute detection thresholds for electrovibration pulses generated using 100 Hz input voltage for durations of 0.2 and 0.5 seconds, simulating a ridge and a button or slider. The measurements were taken under no-turbulence conditions and two different turbulence conditions. Our results revealed that turbulence significantly affects vertical finger movement, average normal force, and the change in force applied to the screen by participants. This combination of factors, along with the 0.2-second pulse duration, makes electrovibration more difficult to perceive or even imperceptible. The 0.5-second electrovibration pulse was perceived better overall and remained unaffected by turbulence. This highlights the strong significance of pulse duration on the absolute threshold of electrovibration. Therefore, to counteract the negative effects of perturbations on perception, electrovibration should be employed for longer durations when perturbations are present.