SketchUp design software.
bolt an outer armor to a frame-like chassis with a buffer of
rubber between them to help absorb the shock. This way,
it’s easy to remove the armor after each match and either
bang it back into shape or replace it. Keep in mind that
the frame itself should be extremely sturdy so it doesn’t
bend out of shape.
Another thing to remember is the simplicity of
component interaction. In other words, how hard is it to
remove a battery? A speed controller? A motor? While we
always want sturdy connections, it’s a good idea to design
the ComBot in a way that makes component removal
quick and easy. Most bots attach all components to a
common “base plate” — one big plate that also serves as
armor for the underside of the ComBot. It’s a great way to
save time between matches since it eliminates extra steps
when working with components.
Once you have a general chassis design sketched out,
you’ll want to do a bit of research to determine the exact
dimensions of the components for the bot. Then, create a
new sketch with everything to scale to ensure that it will
all fit. Keep in mind that most 30 pound ComBots have a
footprint somewhere in the neighborhood of 12” x 12 x
4” to 24” x 24 x 12” — if the bot is outside of that
spectrum, it may be worth considering a redesign.
After completing the chassis design, it’s time to
purchase the required parts and components. Generally,
the easiest way to get the metal needed for the chassis
and armor will be via your nearest metal workshop.
Google “metal works near [Your City]” and give them a
Bot Tip: In designing your robot, it’s helpful to
remember this baseline weight distribution:
•30% (nine pounds) of total weight to the drive
call. Before calling, though, have the exact dimensions in
mind for the sheet metal cuts you’ll need. In other words,
if your armor is a 12 inch cube made of 1/16th inch steel,
you’ll need six 12” x 12” x 1/16” pieces of steel to build it.
THAT’S A WRAP!
In this first installment, we talked about the basics of
building a 30 pound featherweight ComBot, and walked
through the designing process. Next time, we’ll cover how
to put it all together, and include some tips and tricks of
the trade. SV
COMBOTS: ComBots is a combat robotics event
for all ages held multiple times annually. The biggest
ComBots event takes place at the International
RoboGames competition. For more information on
ComBots, visit http://combots.net/.
ROBOGAMES: RoboGames (formerly
ROBOlympics) is an annual competition in the
San Francisco Bay Area featuring robots from around
the world competing in over 70 events. For more info
on RoboGames, see http://robogames.net/.
SUICIDEBOTS: http://SuicideBots.com is a
popular robotics blog, and one of the best sources
of information regarding ComBots, RoboGames, and
other awesome robot stuff.
GOOGLE SKETCHUP: SketchUp is a 3D modeling
software from Google, and can be downloaded for free
JUDGE DAVE'S GUIDE TO WINNING: Judge
Dave's guide to winning is a short article by Dave
Calkins — the founder of ComBots — on winning
robotic combat competitions. The article can be found
72 SERVO 04.2010