Tactile robotic skin

Materials World magazine
3 Jun 2014

A bendable silicon structure could lead to a paradigm shift in robotics. Eoin Redahan reports.

Would you trust a robot with a chicken’s egg? Would you let a heavy-handed humanoid assist the elderly? Many wouldn’t. That is why researchers at the University of Glasgow have developed an ultra-flexible tactile skin to give robots and prosthetics the subtle sense of touch.

While many of today’s sensors can detect objects quickly, they cannot tell whether an object is rough, smooth, tough or fragile. According to lead researcher Dr Ravinder Dahiya, this is because existing electronics are planar and inflexible, which limits the amount of information that can be gleaned from contact. He explains, ‘A human can handle an egg and know it is a fragile thing, but robots cannot do this because there is no feedback coming from the real contact. So, if robots are to be used in future for helping the elderly or in manufacturing alongside human workers, tactile skin will be needed.’

For the tactile skin to be effective, the researchers need to use a flexible material and sensors that can respond to contact within 0.1 milliseconds. To do this, Dahiya is incorporating electronics and sensors onto thin, bendable silicon surfaces that conform to different shapes. He says, ‘It will be something like a foil-to-foil structure. The lowest foil will have all the electronics on it, and the sensing layer will go on top of that. First, we will fabricate the nanowires on wafers, and then we will transfer them onto flexible substrates.’

Dahiya is confident the skin will enable robots to complete a diverse range of tasks. He says it could be useful in hazardous environments such as the Fukushima nuclear power plant – a cluttered environment that is unsafe for human entry. Tactile-skinned robots entering such an environment could exploit contact with obstacles and perform tasks using different parts of the body. He adds, ‘The ultra-tactile flexible skin could also be wrapped around prosthetic limbs. It would be connected with the brain, and that’s how you would control the limbs.’

Dahiya has received £1.07m from the UK Government and £330,000 from the University of Glasgow to develop the technology. In four years’ time, he plans to have demonstrated the tactile skin on prosthetic hands.