PHEUPARD IS THE CAT’S MEOW
Roboticists around the world are in the process of
reverse-engineering the anatomical construction of
cheetahs and other cats in an attempt to develop faster
and more agile legged robots. The latest project — dubbed
the Pneupard — hails from Osaka University.Although still
early in development, the new biomimetic platform stands
out from some of the others through its use of pneumatic
artificial muscles as its primary means of locomotion.
The Pneupard is a creation of researchers Andre
Rosendo and Shogo Nakatsu, under the supervision of
Kenichi Narioka and Professor Koh Hosoda at Osaka
University's Graduate School of Information Science and
Technology. The team has worked extensively with
pneumatic artificial muscles in the past.
Pneumatic artificial muscles can be made from a
rubber tube sheathed in nylon, and contract much like the
real thing when filled with air. They can pack a lot of power
in short bursts and are also highly flexible and impact-resistant, giving them a lifelike quality that is often missing
in robots powered by electric motors. The muscle
contractions — when combined with limbs that accurately
replicate the length, forces, and range of motion of a real
cat — generate a lifelike movement.
Rosendo, the project leader, explains that in the
current prototype, each hind limb has eight active muscles
and the fore limbs (which are under construction) will have
six muscles."The spine will also have muscles, performing
flexion and extension," he says."The main idea of this project is to create a biomimetic platform where
we can replicate feline structure to better understand how they can excel in so many different areas in
locomotion. After grasping their secret, it would be possible to apply that knowledge to future robots."
Rosendo notes that the researchers haven't pre-programmed the muscles by hand; the muscles
actually activate based on EMG signals recorded from a cat walking on a treadmill. The only sensors used
by the robot are force sensors in each foot."The walking is robust enough to withstand random
disturbances, including
asymmetry between the right
and left caused by the artificial
muscle construction method,"
Rosendo explained."We are
compelled to believe that the
musculoskeletal structure found
in animals is 'intelligent' enough
to compensate for disturbances
without requiring a sophisticated
control method."
24 SERVO 04.2013
