Tech Briefs Magazine - August 2022 - 13

Q & A
Artificial Skin Could Lead to a New Generation of
Touch-Sensitive Robots
A team of engineers
from the University of
Glasgow led by Professor
Ravinder Dahiya
developed an artificial
skin with a new type
of processing system
based on " synaptic transistors, "
which mimics
the brain's neural pathways to learn how
to react to external stimuli.
Tech Briefs: What got you started
on this research?
Professor Ravinder Dahiya: Touch sensing
is unique in that it uses sensors distributed
all over our skin. Using skin-type sensing
on a robot is therefore very challenging.
Current technology is not yet ready for
such complex systems. At present, electronics
is mainly realized on planar substrates,
which are not soft and flexible.
Tech Briefs: You refer in your work
to " synaptic transistors. " Can you
explain what that means?
Dahiya: In our bodies, a synapse receives
inputs from various sensors and the synapse
performs a summation of these inputs.
The synapse is the point where, in the
case of nerves, our body learns over a period
of time. For example, if I touch a rough
surface very frequently, my body learns to
differentiate between a rough and a
smooth surface. We have tried to bring
similar functions to our transistors. We
call them synaptic
transistors because
they're able to learn touch-based stimuli.
Tech Briefs: Could you briefly
explain how the touch sensing
works?
Dahiya: We printed a grid of 168 synaptic
transistors made from zinc-oxide nanowires
directly onto a flexible plastic surface.
Then, we connected the synaptic transistor
with the skin sensor present over the palm
of a fully articulated, human-shaped robot
hand.
Tech Briefs, August 2022
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13
When the sensor is touched, it registers a
change in its electrical resistance - a small
change corresponds to a light touch, and a
large change in resistance corresponds to a
harder touch. The change in resistance of
the touch sensor is followed by a circuit
that converts the change in resistance into
voltage spikes whose frequency varies according
to the amplitude of the resistance
change. The spikes are applied to the gate
of the synaptic transistor. If the frequency
of the pulses changes, the transistor's conductance
changes, which is how the transistor
learns.
Tech Briefs: Did you start out
purposely using the body as an
inspiration for how to do this?
Dahiya: Yes, the human skin was an inspiration.
It's well proven and well tested
- it works.
Tech Briefs: Do you have any
thoughts about other applications?
Dahiya: Mobile health is one application,
where each person could have a
smart wearable device that can report
health parameters to one central unit. If
the device worn by each person does
some local computation so it sends more
information, but less unprocessed data to
the central unit, it will be more efficient.
Read the full transcript of this Q&A at
www.techbriefs.com.
http://www.techbriefs.com http://info.hotims.com/82324-736 http://www.techbriefs.com
Tech Briefs Magazine - August 2022

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