Scientists have created compact wearable gadgets that provide rich, expressive, and enjoyable tactile sensations, far exceeding the simple vibrations experienced with current consumer devices.
Human skin is capable of detecting a broad spectrum of sensations, such as a soft squeeze, quick taps, or the rhythmic beat of a heartbeat. In contrast, devices like phones, game controllers, and smartwatches typically rely on basic vibrations to garner the user’s attention. Unfortunately, these abrupt vibrations feel different from most familiar touch experiences and can quickly become bothersome. Researchers at MPI-IS in Stuttgart have introduced cutaneous electrohydraulic (CUTE) wearables to significantly enhance the haptic sensations offered by future consumer electronics.
CUTE wearable devices are powered by electricity and can generate an impressive array of tactile sensations, from pressing against the skin to gentle, soothing touches, as well as vibrations across a broad spectrum of frequencies, both low and high. This innovative method of wearable haptic feedback provides unmatched control over the tactile experiences available to users.
These devices are the result of collaborative work by a multidisciplinary team of MPI-IS researchers from the Haptic Intelligence Department, headed by Katherine J. Kuchenbecker, and the Robotic Materials Department, led by Christoph Keplinger. The team has developed novel hydraulically amplified self-healing electrostatic (HASEL) artificial muscles, enabling wearables to interact with the user’s sense of touch. Upon applying voltage, the soft actuator at the device’s center expands in proportion to that voltage, allowing it to touch and release contact with the skin, similar to a person gently tapping the user’s wrist. Varying the voltage over time lets users customize the haptic feedback to experience different types of touch sensations based on their preferences. CUTE devices are compact, silent, safe, and energy-efficient, and they remain cool during operation. The team showcases these remarkable capabilities in a video.
Potential future uses for CUTE devices encompass aid technologies for navigation, creating tactile sensations to enrich augmented or virtual realities, and enhancing audio and visual feedback in noisy or visually complex situations.
The tactile experiences generated by these devices can convey a variety of feelings, ranging from calming to invigorating, including gentle stroking or tickling, the sensation of a heartbeat, and even the starting and stopping of an engine. Impressively, users perceive nearly all of these tactile cues as pleasant, with the exception of continuous high-frequency vibrations typical of many modern consumer devices. Furthermore, users can accurately identify various cutaneous signals, emphasizing another benefit of CUTE devices compared to widely used electromagnetic actuators.
“Our CUTE devices showcase the potential for creating lightweight wearable systems that offer delightful and expressive tactile communication. Future advancements could expand this technology to larger body areas, generating more intricate sensations, and even exploring human interpretation of haptic cues that have been challenging to replicate,” explains Natalia Sanchez, a Ph.D. student at MPI-IS and the primary author of the publication.
