for the project came a decade ago when
his older brother broke his back while
snow kiting. A family friend who was a
trauma surgeon pointed out that the
back protector that he was wearing was
useless in his case. As luck would have
it, a major study of spinal cord injuries
published around that time backed up that
conclusion.
CRACKING THE PROBLEM
Since then, Edera Safety has spent
more than €400,000 of national funding
and private investment on research to
crack the problem. He recalls: “When we
started, the big issue was that there was
no biomechanical data available where
we could validate our hypothesis that the
kind of devices that we were designing
were right or not. That was where a very
big development journey started.” The
company performed tests on cadavers,
ultimately building a test dummy with a
rotating spine, and a test bed around it.
The research revealed that the spine
naturally has a weak point in the lumbar
area (the small of the back) where it
is braced by neither the pelvis nor the
shoulders, so is vulnerable to hyperrotation.
There are two types of spinal
motion: active, which is the amount of
motion an individual can create by tensing
muscles, and passive, in which someone
else moves the body. Saier found that
the spine can safely rotate farther than
a person’s muscles can turn it, before
causing an injury. “Our device works in
this grey area,” he says.
While it’s easy to make a consumer
product that will restrict motion of the
thoracic spine – it’s called a backpack –
it’s a different story for the pelvis. Saier
adds: “You can’t make something like a
climbing harness, because the market
probably won’t accept it. Therefore we
had to develop a system that, if you have
an rotational impact, and if that rotation
force starts to rise, then the friction at
your pelvis exponentially rises with the
force which is being applied. We are going
for a structure which is able to change
its length if a rotational force is being
applied.”
Having produced some data, and
imagining generally how the device was
going to work, Saier took a new approach
of developing the design automatically,
based on eld testing data from a team
of extreme sports athletes. He explains:
“We started with a simulation where we
said, the point of the optimisation is to
absorb rotational forces on your spine,
but we had no clue how much force was
actually occurring in your spine to cause
an injury. We developed a measuring
system with integrated sensorics that is
actually measuring data out there when
our team riders go riding with it and then
just loops this back into the system.
We used a topology optimisation with
Autodesk that started to redesign and
optimise the design itself. We rebuilt
the results and tested them on the
test bed, and achieved
the results
that we were looking for.
Then we said, ‘Okay, now
we can start converting
this into a physical
mass-produced project.’
That approach is
pretty new.”
He adds that
MEDICAL DEVICES
during development the design of the
product has changed radically. “I would
say that the main concept of how the
lines of force actually run around your
body were found intuitively. We tested
about 125 concepts and designs on the
test bed until we found something that
worked. But the remaining 30% which
really improved the system, that was
something that was coming from the
team riders and generative design. That
was because the program was telling us,
‘you need more material here, and less
there in order to get the same results.’
The width and length variations were
really in uenced by the team riders and
generative data that we got out of it.”
It is clear that exoskeleton designers
have gone to great lengths to optimise
these products to suit the users. While
their market remains limited to a few
applications at the moment, it will not
necessarily remain so. Haas at Ekso
Bionics concludes: “As our technology
continues to improve, we’re not only
going to see wearables in key industrial
applications, but also we will see people
using wearables in their
everyday lives, maybe as
simple as a small shoulder
device to help with yard
work, or something a
person can wear around
their hips and back and
knees to help with
chores around the
house.”
Soft goods in a
range of sizes adapt
the ExoVest to the
wearer’s body
www.ied.org.uk 17
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