Wearable Devices Add Strength 
From: Technology Review - February 2004 - page 26
By: Gregory T. Huang

At Nagasaki University in Nagasaki-City, Japan, mechanical engineer Shunji
Moromugi straps on a pair of what he calls "power pants" and gets to work.
Holding a 16-kilogram barbell on his shoulders, he does 90 squats in 90
seconds without breaking a sweat. That's because the pants contain
computerized sensors that detect what his legs are doing - deep knee bends -
and tubelike artificial muscles, mounted on both sides of the knee, that
expand and contract with flows of compressed air. The artificial muscles are
attached to a steel brace that spans the thigh and calf; when they lengthen,
they extend Moromugi's knee and help him stand more easily.  

These power pants might just be the closest thing yet to a realization of
long-held visions of mechanical systems that improve the mobility of the
elderly and disabled or boost the strength of soldiers and rescue workers.
Where previous wearable robots proved cumbersome and hard to control, this
latest version - a collaboration between Nagasaki University, the University
of Electro-Communications in Tokyo, Japan, and the University of California,
Irvine - is smarter and more practical. Robotics experts say it's an
important step toward building machines that people will actually use. "This
is novel because it's sensing over the entire soft-tissue interface of the
body," says Ephrahim Garcia, a mechanical and aerospace engineer at Cornell
University and a former program manager at the U.S. Defense Advanced Research
Projects Agency. "You need intense amounts of computation to pull it off," he
adds.  

Indeed, the system's tiny sensors are distributed over the legs and hips to
measure signals that muscles give off when they contract. Every few
milliseconds, strain gauges and ultrasonic disk-shaped sensors in cuffs
around the user's legs measure the stiffness and density of the underlying
tissues and communicate wirelessly with a computer that makes sense of the
signals - predicting the user's intended movements on the basis of
experimental data and mathematical models. Then, like a diligent weight-room
spotter, the computer controls the artificial muscles. "We're trying to
reduce fatigue and eventually help disabled people," says Maria Feng, a civil
engineer at UC Irvine and a collaborator on the project. 

The robotic pants are being tested at Nagasaki University for use as a
physical-therapy tool for patients confined to bed. The researchers are also
testing a mechanical glove that allows a user to pick up a coffee cup just by
tensing muscles in his or her upper arm - important for, say, a person who
has lost fine motor control due to a spinal injury or cerebral palsy. In the
next two years, says Feng, the researchers will work out the remaining bugs
and begin widespread testing of the devices in clinics and with patients. 

If all goes well, such human-assist machines might hit the market in five to
ten years. That's because dozens of robotics researchers are working on
related projects, with tens of millions of dollars of funding from DARPA
alone. At the University of California, Berkeley, mechanical engineers have
built robotic "exoskeletons" that connect to people's legs to help them
balance, walk, and run with less effort. The researchers are currently
developing a prototype lower-body suit, powered by rocket fuel, that could
allow soldiers to move more easily over uneven terrain while carrying heavy
equipment. 

So who will be the first to actually use such devices? The consensus among
the researchers is that physical therapy and rehabilitation will be the
initial commercial applications. But that will require streamlining the
technology to make it as safe and reliable as possible. It's still too early
to say whether the real impact will be felt on the battlefield or in the
home. But if the research and development is successful - and wearable robots
prove to be good for your health - they may become fashionable to boot.  

Caption:
Air-powered artificial leg muscles receive instructions from muscle-stiffness
sensors.

From:
http://www.technologyreview.com/articles/innovation40204.asp