Page 63 - Modern Robotics Building Versatile Macines

LEARNING TO WALK 43

CONNECTIONS: BEASTS AND BOTS

Scientists and engineers since the time of Leonardo da Vinci (1452–
1519) have studied biological anatomy and often tried to incorporate
its principles in building such things as flying machines. Generally, it
has turned out that direct imitation of nature’s mechanisms has not
worked well with machines—thus airplanes do not fly the way birds
do, although aspects of their wing structure are similar.
In building robots (sometimes colloquially called “bots”) that have
more of the capabilities of animals and people, today’s researchers
have studied creatures ranging from the cockroach to dogs and even
kangaroos. But at the same time that nature may be teaching the
engineer, the engineer may also be helping to unlock the secrets of
nature. As Raibert pointed out in his 1986 article, “Legged Robots,”
in Communications of the ACM:

One way to learn more about plausible mechanisms for animal loco-
motion is to build legged machines. To the extent that an animal and
a machine perform similar locomotion tasks, their control systems and
mechanical structures must solve similar problems. By building machines,
we can gain new insights into these problems and learn about possible
solutions.

Another way to look at the possible convergence of biological
and mechanical systems of control and locomotion is to consider
how evolution has often guided different types of creatures to
develop similar structures for similar tasks. (For example, insects,
birds, and even mammals [bats] all developed wings for flight). In
a way, robots, too, may be “evolving” similar structures to fit the
niches or applications in which they will increasingly be found in
the future.
Just as Raibert found that relatively simple overall adjustments
(such as changing stride length and posture) were enough to
maintain balance while running, animal research is now suggest-
ing that the nervous system does not “micromanage” locomotion
but instead uses relatively simple overall controls. As Raibert told
Stephen Budiansky, “the mechanical system has a mind of its
own.”