Ultrasonic Friction Modulation While Pressing Induces a Tactile Feedback

Abstract

10th International Conference on Haptics - Perception, Devices, Control, and Applications (EuroHaptics), Imperial Coll London, London, ENGLAND, JUL 04-07, 2016International audienceCurrent touchscreen technology makes for intuitive human-computer interactions but often lacks haptic feedback offered by conventional input methods. Typing text on a virtual keyboard is arguably the task in which the absence of tactile cues imparts performance and comfort the most. Here we investigated the feasibility of modulating friction via ultrasonic vibration as a function of the pressing force to simulate a tactile feedback similar to a keystroke. Ultrasonic vibration is generally used to modulate the sliding friction which occurs when a finger moves laterally on a surface. We found that this method is also effective when the exploratory motion is normal to the surface. Psychophysical experiments show that a mechanical detent is unambiguously perceived in the case of signals starting with a high level of friction and ending to a low friction level. A weaker effect is experienced when friction is increasing with the pressure exerted by the finger, which suggests that the mechanism involved is a release of the skin stretch accumulated during the high-friction state

Tactile Perception of Virtual Edges and Gratings Displayed by Friction Modulation via Ultrasonic Actuation

“…Apart from the studies on sliding-finger, it has been shown that a click effect, as in key press, can be created by reducing the friction as the user presses on an ultrasonically actuated touch surface [23], [26], [30], [31]. Tashiro et al [30] have rendered the feeling of buckling and restitution of mechanical buttons using Langevin-type ultrasonic transducer.…”

“…They argued that the perception of button press and release are due to momentary slippage of the finger over the surface, which occurs when the friction of the surface is reduced by ultrasonic actuation. Unlike [30], Monnoyer et al [31] argued that the feeling of click occurs due to a sudden release of stress at the fingertip, which is accumulated when the friction of surface is high. Recently, it has been shown that there is an optimal value of finger impedance that leads to a stronger perception of haptic click effect [26].…”

The Perception of Ultrasonic Square Reductions of Friction With Variable Sharpness and Duration

“…Beyond the rendering of textures and shapes, the applications for controlled friction modulation are becoming more diverse including new techniques for button-click rendering [36], [37] or haptic enrichment of musical experiences [38]. It is therefore essential to continue extending our understanding of the parameters mediating subjective perception of frictional signals in order to develop novel and more realistic types of haptic feedback.…”

Feeling multiple edges: The tactile perception of short ultrasonic square reductions of the finger-surface friction

“…The development of these novel interfaces raised the interest in touch based human-machine interactions and highlighted the lack of natural touch feedback in the existing generation of tactile displays. As the applications for controlled friction modulation are ever-growing [1]- [3], the development of a high-fidelity strategy for tactile rendering is needed but faces the limitation that little is known about the sensory mechanisms mediating our perception of frictional cues. Currently, multiple solutions are being explored to deliver improved haptic feedback on existing mobile platforms such as smartphones or tablets.…”

“…While much research has focused on periodic signals [10], [11], little is known about how virtual geometric features (e.g: buttons, edges, patterns) should be designed on friction-based tactile displays. Recent research has shown that touch is very at accurate at perceiving the changes in friction even when they are evanescent [12], which enables the use of transient signals in order to generate meaningful feedback [1]. A better understanding of the tactile perception of short reductions of friction will also contribute to the definition of a tactile pixel, which is currently a major challenge for the development of tactile displays with haptic feedback [13], [20].…”