Pinching Tactile Display: A Cloth that Changes Tactile Sensation by Electrostatic Adsorption

TL;DR

This work introduces the Pinching Tactile Display, a cloth that dynamically changes tactile sensation through electrostatic adsorption to provide uniform, full-surface vibrotactile cues without compromising fabric softness. By applying square-wave voltages to a conductive fabric via an insulating glove, the system modulates electrostatic friction to evoke diverse tactile textures across the entire cloth. User studies with six participants show that increasing voltage mainly increases roughness and that a wide range of sensations can be produced while preserving cloth-like qualities; frequency has a comparatively smaller effect. The approach holds promise for immersive VR, tactile online shopping, and wearable textiles, though it requires gloves and could benefit from exploring alternative fabrics, waveforms, and conductive patterns to broaden expressiveness and user comfort.

Abstract

Haptic displays play an important role in enhancing the sense of presence in VR and telepresence. Displaying the tactile properties of fabrics has potential in the fashion industry, but there are difficulties in dynamically displaying different types of tactile sensations while maintaining their flexible properties. The vibrotactile stimulation of fabrics is an important element in the tactile properties of fabrics, as it greatly affects the way a garment feels when rubbed against the skin. To dynamically change the vibrotactile stimuli, many studies have used mechanical actuators. However, when combined with fabric, the soft properties of the fabric are compromised by the stiffness of the actuator. In addition, because the vibration generated by such actuators is applied to a single point, it is not possible to provide a uniform tactile sensation over the entire surface of the fabric, resulting in an uneven tactile sensation. In this study, we propose a Pinching Tactile Display: a conductive cloth that changes the tactile sensation by controlling electrostatic adsorption. By controlling the voltage and frequency applied to the conductive cloth, different tactile sensations can be dynamically generated. This makes it possible to create a tactile device in which tactile sensations are applied to the entire fabric while maintaining the thin and soft characteristics of the fabric. As a result, users could experiment with tactile sensations by picking up and rubbing the fabric in the same way they normally touch it. This mechanism has the potential for dynamic tactile transformation of soft materials.

Figures (6)

• Figure 1: Principle of the Pinching Tactile Display. (a) Without Voltage (b) With Voltage. Applying a voltage to a conductive fabric creates a charge distribution that generates an electrostatic force on the skin and a frictional force. By periodically varying the frictional force, the skin in contact is periodically deformed. As a result, the user feels vibratory stimulation.
• Figure 2: System Overview. When the switch is turned on, current flows, causing a voltage drop across Resistor 1, resulting in 0V across the Conductive Cloth. Conversely, when the switch is off, no current flows, resulting in no voltage drop across Resistor 1 and a high voltage across the Conductive Cloth. The switching mechanism is controlled by the pulse generator and a transistor. The switch is activated (turned on) when voltage is applied to the transistor and deactivated (turned off) when no voltage is applied. This configuration allows a periodic voltage to be applied to the conductive cloth.
• Figure 3: System setup for evaluation. The system consists of a conductive cloth, a DC-DC converter for booster of voltage, a MOS-FET for transistor, Arduino for pulse generator and a power supply.
• Figure 4: Experimental procedure. (a) Subjects answered questions about the tactile sensation of the conductive cloth. (b) Subjects selected the most similar tactile sensation cloth among the 16 prepared fabrics. (c) Subjects answered a 5-point Likert scale for roughness, thickness, stiffness, and warmth based on four fabrics: jeans, voile, gauze, and towels.
• Figure 5: Distribution of means of Likert scale responses for each voltage and frequency.