Researchers at the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart have developed cutaneous electrohydraulic (CUTE) wearable devices, revolutionizing the range of haptic sensations future consumer products can offer.
CUTE devices are compact and comfortable, and they can deliver rich and pleasant haptic sensations to the skin. Image Credit: Max Planck Institute for Intelligent Systems
Human skin is highly sensitive and capable of detecting a range of sensations, from a gentle squeeze to rapid taps or the rhythmic beat of a heartbeat. In contrast, devices like smartphones, gaming controllers, and smartwatches typically rely on basic vibrations to communicate with users. These quick, repetitive vibrations often feel unnatural compared to the diverse touch experiences we encounter daily and can become irritating over time.
To address this, researchers at the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart have developed cutaneous electrohydraulic (CUTE) wearable devices to expand the range of tactile sensations future consumer products can provide.
CUTE devices use electrical energy to produce a wide array of tactile effects, including soft pressure on the skin, slow and calming strokes, and vibrations at both low and high frequencies. This innovative haptic feedback system gives users an exceptional level of control over the sensations they experience, moving beyond the limitations of traditional vibration-only technologies.
The development of these devices was led by an interdisciplinary team from MPI-IS, combining expertise from the Haptic Intelligence Department under Katherine J. Kuchenbecker and the Robotic Materials Department headed by Christoph Keplinger.
At the core of these devices are hydraulically amplified self-healing electrostatic (HASEL) artificial muscles, a novel technology that allows the devices to engage directly with the sense of touch. When voltage is applied, the soft actuator at the center of the device expands in proportion to the voltage level, creating a dynamic interaction with the skin. This expansion can mimic natural touch, such as a hand gently pressing or tapping the user’s wrist. By modulating the voltage, the haptic feedback can be customized to provide a variety of sensations tailored to the user's needs.
CUTE devices are designed with practicality in mind. They are compact, quiet, safe, and energy-efficient, maintaining a cool temperature even during extended use. The research team has showcased these impressive capabilities in a demonstration video.
The potential applications for CUTE devices are broad and exciting. They could serve as assistive technologies, providing tactile guidance to users with visual or auditory impairments. They also offer opportunities to enhance virtual and augmented reality by incorporating realistic touch sensations, and they could complement traditional audio and visual feedback in noisy or visually overwhelming environments.
CUTE devices can create a variety of tactile sensations, ranging from soothing strokes or tickles to the feeling of a heartbeat or the vibration of an engine starting and stopping. Users have reported that most sensations are enjoyable, with the exception of continuous high-frequency vibrations, which resemble the feedback from many current consumer devices and are less pleasant. Moreover, users were able to accurately distinguish between different tactile signals, demonstrating the precision and versatility of CUTE devices compared to standard electromagnetic actuators.
This innovative technology opens the door to a new realm of haptic feedback, with the potential to revolutionize how we interact with wearable devices and other touch-based systems.
Our CUTE devices demonstrate the feasibility of creating lightweight wearable systems that provide pleasant and expressive tactile communication. Future developments could see this technology applied to larger areas of the body, producing more complex sensations, and even studying human perception of haptic cues that were previously difficult to create.
Natalia Sanchez, Ph.D. Student and Study First Author, Max Planck Institute for Intelligent Systems
Journal Reference:
Sanchez‐T, N., et al. (2024) Cutaneous Electrohydraulic (CUTE) Wearable Devices for Pleasant Broad‐Bandwidth Haptic Cues. Advanced Science. doi.org/10.1002/advs.202402461.