bots IN BRIEF
OUT ON A LIMB
Some of the most interesting forms of locomotion in the
animal kingdom come from creatures without bones. We're
talking cephalopods — like octopi — who use their tentacles to
both "walk" and move in a bunch of other ways, often while
carrying objects. This has inspired researchers from the Italian
Institute of Technology and Kings College London to design a
new sort of quadruped robot that walks around on air-powered
soft tentacles instead of legs.
This quadruped is called a continuum robot which means
that it's got limbs (or arms or manipulators or what have you)
that are curvy and flexible. The amount of curvature in each leg
can be adjusted by altering the air pressure inside the three air-filled tubes that act as muscles and bones, and by doing this
rapidly and in the right sequence, the robot can wiggle its way
across a variety of surfaces at a speed that's somewhere between
silly and menacing.
One particularly nice feature about air-filled limbs is that
they're inherently compliant which is a fancy robot term for
bendy. They make great shock absorbers, and you can also beat
on them with stuff and they won't break — mostly because
there's nothing in there to break; they're just tubes with air
inside. When fully inflated, the limbs are nearly rigid; they're
springy when partially inflated, and they're soft when uninflated
to the point where the robot can stuff itself into small spaces.
At this point, the engine (whatever is providing compressed
air) isn't mounted inside the robot itself, but it looks like there's
plenty of room in there for some solenoids and a gas generator
or something like that. The researchers suggest that robots like
these might be adaptable to a wide variety of tasks, ranging from
planetary exploration to swimming to mine detection.
Usually, you think of robot swarms as consisting of
lots and lots of similar robots working together, but
now we’re starting to see swarms of heterogeneous
robots, where you get different robots combining their
powers to make each other more efficient and more
The focus of this type of research is
communication: getting a flying robot to be able to
communicate with a swarm of ground robots by
relying exclusively on visual feedback from LEDs. All
you need to get this to work are lights, cameras, and
some mildly intelligent robots.
Since the ground robots can't see very far, they
rely on a quadrotor to scout ahead and estimate the
parameters of upcoming obstacles. Then, the quadrotor
instructs the swarm on the ground how to team up to
best overcome those obstacles.
20 SERVO 12.2012