Page 46 - Build Your Own Combat Robot

Chapter 2:
Getting Started
Now, it is time to add the weapons to the design process. You need to design a 27
support structure to support the weapons and their actuators. The support struc-
ture should be mounted to the main frame, and the support structure needs to be
very strong. As Newton’s Second Law says, “For every action, there is an equal
and opposite reaction.” In other words, any force your weapon imparts onto an
opponent will elicit equal reaction from the opponent onto your bot. Thus, the
weapon support structure needs to be able to withstand those forces. Chapters 9
and 10 discuss construction and weapons techniques.
The last part of the mechanical design process is the armor. You should design
your armor to be replaced, because it will inevitably get damaged during combat.
You don’t want to damage your own bot just trying to replace the armor, so it
needs to come off fairly easily—when you want it to. Sometimes the armor and the
frame are the same thing. In other words, there is no armor other than the frame itself.
Chapter 9 discusses the various materials that make good armor.
At any time during the mechanical design process, you can select which radio
control system and “robot brains” you want to use. For driving a bot, you need at
least two control channels—one for forward and reverse, and the other for turn-
ing left and right. This is true for bots that have channel mixing. With no mixing,
you would use one channel for the left wheels and one for the right wheels. Addi-
tional channels are for controlling the special features.
You might want to automate some bot functions, like shooting a spike when
the opponent gets within 1 foot of your bot. Here is where you specify the types of
sensors for detecting the opponent and figure out how to mount them inside your
bot. You’ll probably need to have a microcontroller inside the bot to process and
interpret the sensor results in order to control the weapon. Before you implement

FIGURE 2-3
A robot showing
how badly its
armor was
damaged at
a BotBash
tournament.
(courtesy of
Andrew Lindsey)