Page 53 - Robot Builder's Bonanza

22 ANATOMY OF A ROBOT

plastic glued to both sides of a layer of densely compressed foam. You can cut it with a
knife or small hobby saw. Great stuff for quickie- made bots. I talk about foamboard and
similar materials in Chapter 14, “Rapid Prototyping Methods.”
• Aluminum. If you want to go metal, aluminum is the best all- around robot- building mate-
rial, especially for medium and larger machines. It’s exceptionally strong for its weight.
Aluminum is fairly easy to cut and drill using ordinary shop tools. There’s more on building
robots with aluminum in Chapter 11, “Working with Metal.”
• Tin, iron, and brass. Tin and iron are common hardware metals that are used to make
angle brackets and sheet metal (various thicknesses, from 1/32″ on up), and as nail plates
for house framing. Cost: fairly cheap. See Chapter 13, “Assembly Techniques,” for ways
to use common angle brackets in your robot construction plans.
• Steel. Although sometimes used in the structural frame of a robot because of its strength,
steel (and its close cousin stainless steel) is difficult to cut and shape without special tools.
Ideal for combat robots. As this book concentrates on small, lightweight, and easy- to- build
tabletop bots, we’ll leave the discussion of steel at this.

Locomotion Systems

Locomotion is how a mobile robot gets around. It performs this feat in a variety of ways,
typically using wheels, tank tracks, and legs. In each case, the locomotion system is driven by
a motor, which turns a shaft, cam, or lever.

WHEELS
Wheels are the most popular method for providing robots with mobility. There may be no
animals on this earth that use wheels to get around, but for us robot builders it’s the simple
and foolproof choice. Wheels, like those on the robot in Figure 2-10, can be just about any
size, limited only by the dimensions of the robot and your outlandish imagination. Turtle- sized
robots usually have small wheels, less than 2″ or 3″ in diameter. Medium- size rover- type robots
use wheels with diameters up to 7″ or 8″. A few unusual designs call for bicycle wheels, which,
despite their size, are lightweight but very sturdy.

Figure 2-10 Wheels are the most
popular way to make a robot move. The
size, shape, and even the location of
the wheels can vary, though two wheels
counterbalanced on one or both ends of
the bot is the most common design.
(Photo courtesy Parallax Inc.)

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