http://www.newscientist.com/news/news.jsp?id=ns99994750
18:27 05 March 04
NewScientist.com news service
A 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, or 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 that contains the engine, control system and a
space for the payload, says project leader Homayoon
Kazerooni.
Centre of gravity
Although the device itself weighs a hefty 50 kilograms, the pilot
should not notice this because the machine takes its own weight,
with the control system ensuring that the centre of gravity is
always within the pilot's footprint.
In addition to its own weight, it will carry a 32 kilogram payload
within the backpack. To the pilot this would feel like they were
carrying just 2 kilograms, says Kazerooni.
Later this year they will begin trying a new more compact engine
that is more than twice as powerful and should make it possible to
carry loads of nearly 60 kilograms. "If the payload goes even
higher then the pilot takes the extra weight," he says.
Hands free
"The key element is that the pilot needs no joystick, keyboard or
buttons to operate it," says Kazerooni, 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. "You just
push your leg and it moves," he says.
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
hours.
But there are plans to try a quieter, cleaner type of engine. This
kind of motor would run on hydrogen peroxide, which expands rapidly
without combusting when it comes into contact with a
catalyst.
The system will be demonstrated at the DARPA Technical Symposium in
Anaheim, California, between 9 and 11 March.
Duncan Graham-Rowe
