A team of engineers led by Northwestern University has developed a new wearable device that stimulates the skin to deliver complex sensations. The thin, flexible device adheres to the skin and provides realistic sensory experiences. While it is suitable for gaming and virtual reality, researchers also see potential applications in healthcare, such as helping people with visual impairments feel their surroundings or providing feedback to individuals with prosthetic limbs.
The study was published in the journal Nature on November 6. The device is part of ongoing research in wearable technology by John A. Rogers, a bioelectronics pioneer at Northwestern University. It builds on his team's previous work on "epidermal VR," which uses miniature vibrating actuators to communicate touch across large areas of the skin.
"Our new miniaturized actuators for the skin are far more capable than the simple 'buzzers' that we used as demonstration vehicles in our original 2019 paper," Rogers said. He explained that these devices can deliver controlled forces across various frequencies without continuous power application. They can also provide a gentle twisting motion at the skin's surface to enhance realism.
Rogers co-led this research with Yonggang Huang from Northwestern, Hanqing Jiang from Westlake University in China, and Zhaoqian Xie from Dalian University of Technology in China. Jiang's team developed structures enabling twisting motions.
The device consists of a hexagonal array of 19 small magnetic actuators encapsulated within silicone-mesh material. Each actuator delivers different sensations like pressure, vibration, and twisting. Using Bluetooth technology, it receives data about surroundings for translation into tactile feedback.
The device operates efficiently due to its "bistable" design, which allows it to remain in two stable positions without constant energy input. It stores energy when actuators press down and releases it when they push back up. This design enables longer operation on a single battery charge.
"Instead of fighting against the skin, the idea was ultimately to actually use the energy that's stored in skin mechanically as elastic energy and recover that during the operation of the device," said Matthew Flavin, first author of the paper and now an assistant professor at Georgia Institute of Technology.
Huang's team conducted computational modeling to optimize how the device interacts with skin through electromagnetic actuation. "It is essential that this bi-stability design can be universally applied to all types of human skin," Huang stated.
To test its effectiveness, researchers blindfolded subjects who then navigated paths with obstructing objects using feedback from the device. Subjects adapted quickly after training sessions by substituting visual information with mechanical feedback similar to using a white cane but integrating more information.
"As one of several application examples, we show that this system can support a basic version of 'vision' in haptic patterns delivered based on data collected using LiDAR available on smartphones," Rogers noted.
The study is titled "Bioelastic state recovery for haptic sensory substitution."