September 13, 2019

Octopus-inspired tech senses without central ‘brain’

By Robert Scammell

Researchers have created prototypes of a stretchable silicone structure that can sense and react to stimuli without any centralised processing, or ‘brain’.

Where traditional robots and computers carry out decision-making centrally, such as in a central processing unit (CPU), the ‘soft tactile logic’ approach can make more localised decisions.

The team that developed the prototypes, from North Carolina State University, says the octopus-inspired tech could have useful applications in areas such as prosthetics and soft robotics.

“We call this ‘soft tactile logic,’ and have developed a series of prototypes demonstrating its ability to make decisions at the material level – where the sensor is receiving input – rather than relying on a centralised, semiconductor-based logic system,” said Michael Dickey, co-corresponding author of a paper on the work and Alcoa Professor of Chemical and Biomolecular Engineering at North Carolina State University.

“Our approach was inspired by octopuses, which have a centralised brain, but also have significant neuronal structures throughout their arms. This raises the possibility that the arms can ‘make decisions’ based on sensory input, without direct instruction from the brain.”

How does soft tactile logic work?

The silicon structure contains channels containing metal that is liquid at room temperature. This effectively acts as a “squishy nervous system”.

Pigments on the silicon structure react to temperature change. If the silicone is stretched or pulled, the liquid metal’s electrical resistance increases. This increase raises the temperature of the structure, which in turn causes the colour to change.

The change in colour demonstrates the ability to sense and react to touch stimuli. The researchers took this principle further by redistributing the electrical current generated from touch to activate motors and turn on lights.

Although these outputs are limited, Dickey believes that the soft tactile method could open new doors for electrical engineering.

“This is a proof of concept that demonstrates a new way of thinking about how we can engineer decision-making into soft materials,” said Dickey.

“There are living organisms that can make decisions without relying on a rigid centralised processor. Mimicking that paradigm, we’ve shown materials-based, distributed logic using entirely soft materials.”

The findings were published in the journal Nature Communications.

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