New Wearable Device Could Provide a Higher Touch Perception in VR Applications

Tencent's Robotics X Laboratory and City University of Hong Kong (CityU) created a wearable tactile rendering system that replicates touch sensations with high spatial resolution and a rapid response rate. The team implemented this device in a braille display and provided touch sensations in the metaverse for VR shopping and gaming. Additionally, it has potential applications for astronauts, deep-sea divers, and those who must wear thick gloves.

Their thin and flexible electro-tactile actuator can be placed into a finger cot. It also displays varying sensations, including vibration, pressure, and texture roughness. Rather than DC pulses, the wearable device operates under 30V thanks to the high-frequency alternating simulation strategy the researchers developed. As a result, the tactile rendering is safe and comfortable to wear.

They proposed a super-resolution strategy that renders "tactile sensation at locations between physical electrodes, instead of only at the electrode locations." That allows them to achieve a higher spatial resolution of their simulators from 25 to 105 points, providing the wearer with a more realistic tactile perception.

"Our new system can elicit tactile stimuli with both high spatial resolution (76 dots/cm2), similar to the density of related receptors in the human skin, and a rapid response rate (4 kHz)," said Mr. Lin Weikang, a PhD student at CityU, who developed and tested the device.

The team tested out the wearable device to demonstrate potential applications. First, they made a Braille strategy proposal for those with a visual impairment. This would work by breaking down the alphabet and numerical digits into individual strokes, which are presented in the same written order. Wearing the system on a fingertip allows the user to recognize the alphabet via the sensor by feeling the direction and sequence of the strokes.

"This would be particularly useful for people who lose their eye sight later in life, allowing them to continue to read and write using the same alphabetic system they are used to, without the need to learn the whole Braille dot system," Dr. Yang noted.

The system can also be used for VR/AR applications and games, providing a sense of touch in the metaverse. Highly flexible and scalable electrodes would then cover larger areas like the palm. The team's demonstration shows the wearer virtually sensing the texture of clothes in a virtual clothing store. Users can also feel a little itch on their fingertips when a VR cat licks that area. Petting the cat enables the wearer to feel a variance in the roughness while the strokes change speed and direction.

Additionally, it can transmit fine tactic details through thick gloves. The team placed the system's thin, light electrodes in flexible tactile sensors on a safety glove. The sensor collects the pressure distribution on the outside of the glove and transmits that data back to the wearer via tactile stimulation. Their experiment showed that the user precisely and quickly located a steel washer with a 1 mm radius and 0.44 mm thickness based on the glove's tactile feedback. This shows that astronauts, firefighters, deep-sea divers, etc., wearing thick protective suits or gloves could benefit from the system's high-fidelity tactile perception.

"We expect our technology to benefit a broad spectrum of applications, such as information transmission, surgical training, teleoperation, and multimedia entertainment," added Dr. Yang Zhengbao, Associate Professor in the Department of Mechanical Engineering of CityU, who co-led the study.