Build Your Own Combat Robot

54 Build Your Own Combat Robot
FIGURE 3-8
Go-kart wheels give
a robot the look of
a racing car.
time hold the inner part of the tire together, resulting in a puncture-proof combination.
Another option is to fill the tires with foam, which a lot of experienced robot
builders use to keep down the weight of their robots.
Traction on the combat floor is important. Go-kart tires are made for extremely
hard use, and their fairly soft surface has pretty good traction (see Figure 3-8).
Many of the pneumatic tires you might find in surplus houses or hardware stores
have molded treads for traction purposes. The industrial cart tires mentioned earlier
with the hard rubber tires are not pneumatic, but they can be modified with
grooves, which some builders believe give traction to the wheels. Cutting with a
knife or saw is not recommended, though, as any sharp cuts or gouges can easily
propagate into a crack that can eventually sever the tire. Grinding the grooves is recommended
instead.
Mounting and Supporting the Wheels and Axles
The mounting of the wheel to the axle and other parts of the locomotive system is
the next important consideration. Not only must the complete wheel assembly be
securely attached to the axle, but the wheel should ideally be able to be rapidly removed
if repairs and replacements are necessary between matches. An easily removable
wheel can make the difference in winning or losing a competition. You
can attach wheels to robot platforms in numerous ways. Attachment methods depend
on the wheel configuration desired. A typical arrangement might be the one
illustrated in Figure 3-9. Many robot designs involve some sort of metal box chassis
with internal motors and associated equipment, and external wheels attached