Page 61 - Build Your Own Combat Robot

OVING is what many might call a robot’s primary objective; it’s
what separates a robot from a plain old computer sitting on the floor. Whether you
use wheels, legs, tank treads, or any other means of locomotion, you’ve got to figure
out a way for your machine to traverse across the floor or ground, unless you’re
trying to build a flying or marine-based machine. The way you make your robot
move will be one of the most important considerations in the design of your com-
bat robot.
In this chapter, we’ll concentrate on locomotion methods that are easy to con-
struct and most effective for large robots and combat machines. We’ll also discuss
the drawbacks of some methods for combat robot applications. Several methods
of locomotion have been successfully used in combat and other large robots.
These are legs, tank-type treads, and various other configurations and styles of
wheels. Yes, some really cool machines have used other means to get across the
floor, but “cool” and effective are sometimes very different.
Legs are often one of the first types of locomotion we envision when we think of
robots. For most people, robot means a walking bot like C3P0 in Star Wars or
Robby from Forbidden Planet. However, we must remember that these creatures
were just actors wearing robot suits to make them appear as walking machines.
Walking is actually a difficult task for any creature to perform, whether its human
or humanoid. It takes babies nine months or longer to master the act; and for several
years after that, they’re tagged with the title of “toddler.” A child’s brain is con-
stantly learning and improving this complex process each day. Bipedal (two legs)
walking is really controlled falling—stop in the middle of taking a step and we’d fall
over. Impede the process with a few beers too many, and our built-in accelerometers
(our ears’ semi-circular canals) feed us wrong information and we stumble.

R obots with Legs

Watch a person walking and you see them swaying from side to side with each
step to keep balanced. Try race walking and see how exaggerated you must twist
your body to speed up walking. While walking, we always strive to keep our cen-
ter of gravity over one foot if only for a fraction of a second. If you count the number
of joints and motions in a person’s leg, you’ll realize that these joints are
multi-axis joints—not just single-axis joints that we might have in a robot. Many
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