Novel gel could give robots sensory skin

US researchers are experimenting with synthetic skin for robots which would enable them to sense mechanical stimuli and respond chemically.

The idea was devised by researchers at the University of Pittsburgh and validated by a team at the Massachusetts Institute of Technology (MIT).

‘Think of it like human skin, which can provide signals to the brain that something on the body is deformed or hurt,’ said Anna Balazs of Pittsburgh. ‘This gel has numerous far-reaching applications, such as artificial skin that could be sensory – a holy grail in robotics.’

First the team at Pittsburgh made predictions regarding the behaviour of Belousov-Zhabotinsky (BZ) gel, a material that was first fabricated in the late 1990s and shown to pulsate in the absence of any external stimuli. In fact, under certain conditions, the gel sitting in a petri dish resembles a beating heart.

They predicted that BZ gel not previously oscillating could be re-excited by mechanical pressure. The prediction was validated by MIT researchers, who proved that chemical oscillations can be triggered by mechanically compressing the BZ gel beyond a critical stress.

The gel could serve as a small-scale pressure sensor for different vehicles or instruments to see whether they’d been bumped, providing diagnostics for the impact on surfaces. Balazs said that inspiration for the technology came from observations of the mimosa plant.

‘The plant leaves fold inward and droop when touched or shaken, reopening just minutes later. I knew there had to be a scientific application regarding touch, which led me to studies like this in mechanical and chemical energy.’