VOICEOVER: Meet ART. The Amphibious Robot Turtle.
As its name suggests art is a robot that can swim in water and walk on land.
And it's all down to a clever party trick. It has legs that can turn into flippers.
According to the team of researchers behind the 'bot', this shape-shifting
ability has the potential to make art more efficient than existing amphibious machines.
ROBERT BAINES: So some robot designers will say, okay
we know propellers work well in water to move around, we know wheels work well
on land - so let's make a robot - put propellers on it and put wheels on it.
In water a propeller might be very efficient but on land,
it doesn't really allow the robot to move.
But it ends up being additional weight on the robot, additional space.
VOICEOVER: This is where art makes its efficiency gains.
Instead of having separate components to move in water and on land, ART's
morphing limbs can adapt to suit both, removing the need for redundant parts.
ROBERT BAINES: So these are the two modes of the morphing limb. So on
my right here we have the flipper mode, which is this flat hydrodynamic shape.
And then on my left here we have the leg mode which is this shape - cylindrical and
load bearing and we have a little curvature on the end of the limb that gives it some
surface area so that it can contact the ground and not not just fall over.
VOICEOVER: Creating this limb required some principles from
the rapidly growing field of soft robotics.
ROBERT BAINES: on the outside there's a balloon that inflates and gives the
limb its shape and on the inside, bonded to this balloon, is a material that changes its
stiffness. When it's heated up past a certain temperature it becomes very soft and pliable.
And so using these materials we can transition from The flipper to the leg or from the leg to
the flipper, that can walk on land or swim in water - or transition between the two.
VOICEOVER: But creating adaptable limbs was just the first step.
Next they needed to program ART with patterns of movement known as gaits to
make use of these morphing materials. And for inspiration as you might have guessed
they turned to turtles and their terrestrial counterparts tortoises.
ROBERT BAINES: So the walking gait is called a creeping gait. This isn't the
fastest gait but it's similar to a tortoise - so if you look
at a tortoise they have sort of this amble where they're lifting their legs up slowly,
one by one. And this is what this creeping gait was inspired by.
So we also have a gate that's inspired more by, for example sea turtles, and this is
the quintessential flapping motion you would see a sea turtle doing - sort of
a quasi-figure eight pattern in which the flipper is coming up and then coming down
and it's changing its angle with respect to the the forward direction all the while.
VOICEOVER: These two gates seem to do the job well on land and in water but ART ran into some
difficulty on the awkward terrain between the two environments which is often sandy stony or muddy,
and ART often slipped or got stuck. So the team opted for another less elegant solution.
ROBERT BAINES: So we looked at beaching sea turtles and basically the locomotion
strategy they use, which is lying on their stomachs and then pulling
themselves forward. And is not particularly graceful but shifting the gait really gave
us a little more versatility in where the robot could go.
VOICEOVER: The researchers calculated metrics for ART's efficiency by measuring how much power it
used and how fast it was able to move for its weight in different settings. And armed with
its morphing limbs and shifting gaits, ART was able to match or outperform many exclusively
terrestrial or exclusively aquatic robots - while still being able to move in both environments.
Of course art is still a work in progress. Right now, for example, it's tethered meaning its power
supply and programming centre aren't housed within the body itself. But in the future
the team hopes that morphing amphibious 'bots' loaded with sensors or cameras like
you can see here could be used for things like ecological monitoring or even disaster response.
And their shape-shifting approach to robot design doesn't have to stop there.
ROBERT BAINES: So I don't think it's necessarily confined to just a robot with morphing limbs.
This idea can be extended where we have robot bodies that morph more drastically to specialise
for different types of locomotion, different tasks. I think if people see the potential
efficiency gains, shape morphing lends itself to adaptability in a variety of robotic applications