Page 37 - Anatomy of a Robot

02_200256_CH02/Bergren 4/17/03 11:23 AM Page 22
22 CHAPTER TWO
another person’s mind. To communicate verbally, we form our thoughts, utter
them, watch the reaction in the other person, and alter our statements based on his
or her reaction. All these actions cannot be perfectly executed and always have
unintended results. On this point, read Ronald David Laing’s book The Politics of
Experience.
A city with a large convention center suffered a flood inundating the first floor of the
center. When firemen showed up at the convention center during the flood, they were
amazed to hear rushing water every 45 seconds. Water gushed down the escalator from
the second floor, stopped, and then repeated over and over. It turns out somebody had
designed a smart feature into the elevator system. Since there were only two floors, why
even bother putting in floor buttons? Just sense the motion of people coming into the
elevator, and take them to the other floor. So the elevator was patiently going to the
ground floor, opening up to allow the floodwater to come in, and bringing it to the sec-
ond floor. Sensing a great deal of traffic, the elevator returned to the ground floor for
more “people.” All the while, the control system was perfectly content with its actions.
So my advice about the control system is this. Keep it simple, unless you’re just
experimenting and fully prepared to fail.
Let’s take a step back and look at your original goals. If you’ve written specifications
for the robot (and kept them simple), you have a limited list of tasks that the robot must
perform. All you have to do is build a robot that can execute the tasks on its plate.
Where do we start designing a robot so it can do such things? For starters, we can
look to nature for analogous designs. Nature abounds with control systems worthy of
emulation. However, our thoughts are commonly rife with anthropomorphic visions of
robots. The first image that springs to mind is of a robot with a head, two eyes, two ears,
a mouth, two arms, and a torso. Are we being led astray by our own instincts?

Distributed Control Systems

Although many arguments have been made for the existence of a distributed intelligence
within the human body, clearly a central control system exists: the brain. Is a central con-
trol system what we really want? This is worth considering before choosing an architecture.
Consider a school of herring. They swim in giant schools, flashing silvery in the deep
blue ocean light. See http://www.actwin.com/fish/marine-pics/anchovie.mpg. As some
tuna come in to attack, the school instantly swerves, divides, and coalesces as if by
magic. It’s a viable survival tactic for the herring. How do they pull off such a feat? Well,