Page 48 - Robot Builder's Bonanza

THE BODY OF THE ROBOT 17

• Or it could be a small motorized cart operated by a strict set of predetermined instructions
that repeats the same task over and over again until its batteries wear out.
• Or it could be a radio- controlled arm that you operate manually from a control panel.

Each is no less a robot than the others, though some are more useful and flexible. As you’ll
discover throughout this book, you’re in control in defining how complex your robot cre-
ations are.

The Body of the Robot

For most robots, its body holds all its vital parts. The body is the superstructure that prevents
its electronic and electromechanical guts from spilling out. Robot bodies go by many names,
including platform, frame, base, and chassis, but the idea is the same. The bodies of robots
differ in size, shape, and style; their type of superstructure; and their overall construction.

ROBOT SIZE, SHAPE, AND STYLE
Robots come in all sizes. Some can fit in the palm of your hand, while others are so big it takes
two people to lift them from the worktable.
Homebrew robots are generally the size of a small cat or dog, although some are as com-
pact as an aquarium turtle and a few as large as Arnold Schwarzenegger (if one of these asks
you, “Are you Sarah Conner?,” answer “No!”). The overall shape of the robot is generally
dictated by the internal components that make up the machine, but most designs fall into one
of the following “categories”:
• Turtle (or desktop)
• Rover
• Walking
• Arms/grippers (also called appendages)
• Android and humanoid

Smaller robots are not only easier to build, but they are also more affordable. Their smaller
size means smaller motors, smaller batteries, and smaller chassis— all of which tend to reduce
price.
Turtle or Desktop
Turtle or so- called desktop robots are simple and compact. As the wording implies, these
creations are designed primarily for “tabletop robotics.” Turtlebots get their name because
their bodies somewhat resemble the shell of a turtle. Researcher W. Grey Walter used the term
to describe a series of small robots he envisioned and built in about 1948. In popular usage,
turtle robots also borrow their name from a once- popular programming language, Logo turtle
graphics, adapted for robotics use in the 1970s.
The turtle category represents the majority of amateur robots (Figure 2-5 shows one of
them). It’s popular among those involved in noncombat competitions— things like maze fol-
lowing or robotic soccer. Turtle robots are most commonly powered by a rudimentary brain
(BEAM robotics, based on simplified electronics, is a good example) or by a small single- chip
computer or microcontroller.

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