Build Your Own Combat Robot

Chapter 14: Real-Life Robots: Lessons from Veteran Builders 327
During the final testing, our bot started the wire meltdown process. We had
used 14-gauge wire in our robot—too small for the current going through it. We used
14-gauge wire since we had a lot of it lying around at work. We planned on getting
bigger wire but never got around to it. As we drove the robot around, people kept
saying, “Someone’s robot is burning up,” and I would grin at them and say it was
mine, telling them my 14-gauge isn’t quite enough for the robot. They all laughed.
Then the second part of the qualification round came up. We had to drive around
the figure-8 course and knock down as many cans as possible.
We knocked down the first set of cans, but the same side of the robot locked up
again. This time, there was no motion and lots of the magical gray smoke was escaping
out of my robot. It was a beautiful scene—gray smoke, a shuddering robot,
and the smell of burnt plastic. Needless to say, we failed to qualify, and Live Wires
failed to make it on the show.
The post-mortem on the robot showed that the 6-mm, left-hand-threaded screw
sheared and caused the drill motor to seize up. After the event, I ran a calculation
and discovered that this screw would shear when the torque exceeded 120 in.-lbs.
I should have run the calculations before the event. Never simply assume a part
will be strong enough for the competition. Always test first! I would have discovered
this problem if I had tested the robot more before the event, but six weeks really
is not a lot of time to build and properly test a robot.
Live Wires didn’t do well in its first competition, but it was a lot of fun to build
and it was truly heartbreaking for us to watch it fail. My experience with Live
Wires is similar to many combat robot builders. When you take a lot of shortcuts
and don’t allow enough time to build the robot properly, you will run into a lot of
problems. It is best to plan everything before you start, and allow plenty of time to
build and test your robot.
By now, you should have enough information to get started building combat
robots. It is a fun and exciting world, so what are you waiting for? Start building
your robot!