ExoskeletonTakes The Strain
human exoskeleton, which could help soldiers and fire-fighters
carry heavy loads, is about to take its first public steps.
Called the Berkeley Lower Extremity Exoskeleton (BLEEX),
it is part of a Defense Advanced Research Projects Agency
venture designed to help foot soldiers carry heavier loads
over even longer distances, by connecting robotic supports
to their legs to reduce the load. Besides helping soldiers,
it could also assist medical personnel carrying wounded
people from disaster areas or fire fighters in hauling heavy
equipment up countless flights of stairs. A human 'pilot'
straps the exoskeleton's legs to their own and dons a large
rucksack, containing the engine, control system and space
for the payload. Although the device itself weighs a hefty
50-kg, the pilot should not notice this because the machine
takes its own weight. In addition, it will carry a 32-kg
payload within the backpack, which, to the pilot, would
feel as if carrying just 2 kilograms. The key element is
that the pilot needs no joystick, keyboard or buttons to
operate it, leaving your hands free for other tasks. This
is because the entire control system is designed to ensure
it moves in concert with the person wearing the exoskeleton.
One simply pushes ones leg and it moves. To drive the powerful
hydraulics necessary for heavy lifting BLEEX has a small
purpose built combustion engine built into it. On a full
tank the system should be able to run for as long as two
A Steam Machine
used for boats, the engine works by injecting steam through
a rear-facing, ring-shaped nozzle into a cylindrical chamber.
As the steam emerges at three times the speed of sound,
it rapidly condenses, generating a shock-wave that pulls
in water through an intake and expels it from the rear,
generating thrust. During the tests, a technician squirted
water into it with a garden hose purely out of curiosity
and to everyone's surprise, the water emerged as a jet of
fine droplets that drenched anyone standing within 20 metres
of it. The engineers later found that shock waves, generated
as steam emerges from the nozzle, were breaking the water
down into a fine spray, which was projected at high speed.
The droplets in the spray are about 10 times the size of
droplets in clouds, and this turns out to be within the
optimum range for extinguishing fires. Moreover, chemicals
injected into the unit mix rapidly with the water in the
mist, and hence, the device will be useful for neutralising
chemical spills or even disinfecting buildings or people
after a biological or chemical attack.