Wearable Haptic Device Creates the Sensation of Touch

Actually feeling a hug from your mother or a friend through a video call may become a reality soon if a team of biomedical researchers from City University of Hong Kong and Northwestern University in the U.S. succeeds in commercializing a wireless virtual reality (VR) concept that works with the user’s skin. The team believes its goal would have great application potential in communications, prosthetic control, and rehabilitation, as well as gaming and entertainment.

Skin is a person’s largest organ. But compared with eyes and ears, it is a relatively under-explored sensory interface for VR or augmented reality (AR). Currently, most VR and AR devices rely on vibrations made on the skin by electrical motors. But they require bulky wires and battery packs attached to the body, limiting their “realism” and applications.

This team has developed an actuator that receives its inputs wirelessly and then simulates “touch” with vibration created by a thin, soft, and adhesive bandage-like device on the skin.

Based on structural mechanics, the pad is comprised of hundreds of functional components, including actuators simulating touch by millimeter-scale mechanical vibration. These components are attached to a thin silicone-coated elastomeric layer about 3-mm. thick. The pad  is breathable, reusable, and can remain attached and working despite the user going through a full range of bending and twisting motions. More importantly, a collection of circuits and antennae embedded in the pad lets it be powered and controlled wirelessly.

The haptic actuators harvest radio frequency power through the large, flexible antenna within a certain distance, so the user wearing the device can move freely without the trouble of wires. The system works when within about three feet of the transmitter, which might not sound far, but it is 10 times the maximum distance of similar technologies.

The haptic actuators require less than 2 milliwatts to create induce a notable sensation, while conventional DC-driven alternatives ones need about 100 milliwatts to produce the same level of vibration.

The team has spent about two years developing this wireless haptic skin device, which involves various disciplines such as mechanical engineering, materials science, biomedicine, physics, and chemistry. The researchers are now running trials with prostheses users to help them feel external stimulation with their prosthetics, such as the shape or texture of an object. The team also believes it could greatly enhance sensory experiences in social media interactions, multimedia entertainment, and surgical training.