Novel artificial nerve system to give robots sense of touch

New York : Researchers have developed an artificial sensory nerve system that can restore sensation to amputees using prosthetic limbs and one day give robots some type of reflex capability. The researchers tested the ability of the system to both generate reflexes and sense touch and found that it can activate the twitch reflex in a cockroach, identify and differentiate letters in the Braille alphabet, as well as accurately detect direction of the motion.

"We take skin for granted but it's a complex sensing, signalling and decision-making system," said Zhenan Bao, Professor at the Stanford University in California, US. "This artificial sensory nerve system is a step towards making skin-like sensory neural networks for all sorts of applications," Bao added.

In the study, reported in the journal Science, the researchers constructed an artificial sensory nerve circuit that could be embedded in a future skin-like covering for neuroprosthetic devices and soft robotics. This rudimentary artificial nerve circuit integrates three previously described components. The first is a touch sensor that can detect even minuscule forces. This sensor sends signals through the second component--a flexible electronic neuron.

Sensory signals from these components stimulate the third component, an artificial synaptic transistor modelled after human synapses. "Biological synapses can relay signals, and also store information to make simple decisions. The synaptic transistor performs these functions in the artificial nerve circuit," said Tae-Woo Lee of Seoul National University in South Korea.

The study describes how the electronic neuron delivered signals to the synaptic transistor, which was engineered in such a way that it learned to recognise and react to sensory inputs based on the intensity and frequency of low-power signals, just like a biological synapse.