New Electronic Skin Detects Pressure From Different Directions
By Chuck Seegert, Ph.D.
A new electronic skin design has the ability to detect not only pressure, but also the direction from which the pressure originates. Modeled on human skin, the stretchable design could have applications in prosthetics and robotics.
The development of electronic skin — or thin, flexible film-like sensors — holds much promise in the area of prosthetics and robotics. Certain designs are specialized for reading brain activity, while others monitor heart rates or detect pressure. Although there have been many electronic skin designs with various capabilities, so far none of them have been able to detect the direction pressure is coming from.
A new design from a research team at the Ulsan National Institute of Science and Technology has been able to achieve multi-directional pressure sensing by mimicking certain structures in human skin, according to a recent press release from the American Chemical Society (ACS). The design is composed of an array of small, dome-like structures that interlock and deform when stretched, poked, or even when air is blown across them. Sensing the direction of stretch is an important part of the natural touch sensation. For example, when we hold a glass of water and it starts to slip, we can detect this and tighten our grip to prevent it from being dropped.
The dome-like structures are modeled on the epidermal-dermal ridges in human skin, according a recent study published by the team in ACS Nano. The microdomes are piezoresistive, and testing performed during the study showed they were able to detect shear, bending, and twisting actions. This sensitivity was enabled by the way the domes interlock, which provides unique signatures, or sensory output patterns, when exposed to different types of deformation. Tests that deployed the electronic device on the skin of a subject’s wrist proved that the device was capable of detecting the mechanical stimuli encountered in that highly mobile anatomical setting.
An electronic skin that is capable of directional pressure sensing could find significant application in the field of prosthetics. The development of sensory feedback for prosthetic devices has accelerated recently with designs that have been deployed in clinical applications, according to a recent story on Med Device Online. These robotic limb replacements are actuated by impulses from the patient’s brain, but sensory feedback is a relatively recent addition that could benefit from increased sophistication.
Image Credit: American Chemical Society