Gimme some skin: 'ticklish' Skin-On interface gives machines a sense of touch

Joseph Flaig

The Skin-On interface could give robots the human touch – or give an authentic look and feel to prosthetic devices (Credit: Marc Teyssier)
The Skin-On interface could give robots the human touch – or give an authentic look and feel to prosthetic devices (Credit: Marc Teyssier)

Ever been tapping away at your phone and thought “This is so impersonal, I wish I could tickle it instead”?

Probably not, but Marc Teyssier has. In the news last year for developing the MobiLimb finger add-on for mobile devices, PhD student Teyssier from Télécom ParisTech and La Sorbonne University has revealed the Skin-On interface in partnership with engineers at the University of Bristol. 

Looking like it could sprout legs and run off at any moment, the fleshy slab is instantly recognisable yet distinctly unsettling. The interface is a lifelike artificial skin, attached to a smartphone in an early demonstration to let users control it with naturalistic gestures including tickling, stroking, twisting and pinching. 

Beyond the initial shock value and the gimmicky phone application, it could have serious uses – or inspire other developers to consider a more human touch. 

Gimme some skin

The project is inspired by Teyssier’s focus on ‘affective touch,’ the slow and sensitive touches that help form bonds – something he says is lacking from our interactions with everyday devices. “For me the best affective touch is human skin,” he says. “It gives a different expressive capability that is not performed on the touchscreen.”

While most approaches to artificial skin focus on sensitivity, Teyssier instead set out to realistically reproduce the three layers of human skin. The top layer of DragonSkin silicone mimics the epidermis, beige pigments and paint giving a realistic appearance. Underneath, a perpendicular grid of conductive Datastretch threads forms the electrodes. At the base is fatty Ecoflex Gel, poured to varying thicknesses. 

The interface picks up gestures using computer vision, which Teyssier admits could be improved. But it is the feel of the skin itself that he says is most important. “The fat layer, and the way we put it together, makes for the comfort of touch.”

The researchers created a phone case, computer touch pad and smart watch to demonstrate the interface’s ability to convey expressive messages for computer interaction with humans and virtual characters. In one example, the intensity of the touch controls the size of emojis. A strong grip conveys anger, while tickling displays a laughing emoji. 

The aim is more ambitious, however. The interface could add a human touch to robots, making them more sensitive to people and enabling tender interactions with biomedical or care devices.

Skin-On might also be a perfect coating for prosthetics, letting users feel a rich range of interactions with an uncannily authentic covering. Sensing and actuator technology has created complex and sensitive prosthetic limbs, but few – if any – give the appearance of natural skin. The interface could ease acceptance of new devices. More importantly, the capacitance of the in-built electrode wires could be adapted to help impart the sensation of touch from more objects, returning naturalistic sensation for amputees. 

Future possibilities

Teyssier is pragmatic. “I think I will not convince anyone to use the skin smartphone,” he says. “It’s more like exploration of the future. I think it’s worth going this way and seeing what the reaction is.” Arguments and discussion will advance the technology, he says.  

Skin-On is weird – but so is life, and artificial skin for robots is a serious research consideration. Improvements to prosthetics is an even more tantalising possibility. Maybe the human touch is exactly why people will engage with it.

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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.

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