Page 34 - Modern Robotics Building Versatile Macines

14 Modern Robotics

• “Control by informative feedback,” where a machine is guided by
the results of previous actions
• A balance between negative (self-correcting) and positive (ampli-
fying) feedback
• The creation of communications networks and their analogy to
nervous systems
• The broad applicability of cybernetics to fields ranging from
computer science to sociology and psychology

In the 1950s and early 1960s, cybernetics became a sort of cul-
tural phenomenon. It offered buzzwords for facile commentators but
also potential areas of exploration for researchers in dozens of fields
and applications.

Cybernetics and Robotic Turtles

In the early 1950s, some practical applications of cybernetics aroused
considerable interest. Grey Walter’s “tortoise” robots, which were
featured in Scientific American, demonstrated how a cybernetic
system could be designed so that it interacted with its environment
(through feedback) and exhibited lifelike behaviors. Primarily an
analog rather than a digital device, the simple robot first checks for
obstacles so it can change its direction of motion to avoid a collision.
Just as humans do this automatically while walking, even while pur-
suing some higher goal (such as the refrigerator), Walter’s tortoise
had the “higher” goal of seeking and moving toward light sources.
This movement was governed by several rules:

• If the area around the robot is dark, the robot searches for light
and moves toward it if found.
• As long as the light level is moderate, the robot continues to move
toward the light source.
• If the light becomes too bright, the robot reverses direction to
avoid becoming “dazzled.”

Depending on how the light sources in the room are arranged, the
result is surprising, unpredictable behavior. Even with only a few