Parts List
ITEM
• Garolite
• Titanium
• GM- 19 Motors
• RW2 Wheels
• Pneumatic System
• 740 mAh Battery
• Speed Controls
• Pico Receiver
One of the last
things that had to be
done once the robot
had been assembled
and wired was the
installation and fabrication of its armor. I again
wanted to mimic Ziggy
as best as possible so I
procured a thin sheet of
titanium to create my
armor form. Getting Ziggy
shaped armor without cutting and
welding the shapes meant that it
could only be done by bending and
cutting the sections to get the
desired shape with hand tools.
SUPPLIER
McMaster.com
TitaniumJoe.com
Solarbotics.com
Solarbotics.com
(Out of production)
ThunderPowerRc.com
BaneBots.com
BaneBots.com
Bot 3-9 speed controls and a third
3-9 to control the flipping valve. An
Airtronics RD6000 super transmitter
controls the whole thing and a Pico
GWS receiver relays the radio signals.
After several hours of labor, I
had created two separate sections
which were ready to mount onto
the robot. Mounting was taken care
of by simply gluing the sections to
the base plate and items that were
attached to the base. Overall, the
design of Get Flippen has proven to
be very effective, yet plagued with
various hang-ups that have cost it
wins in the arena. Once the bugs
are worked out, I am confident that
this robot will be able to win events.
Though it is lacking the consistency
which is required to win, it has
already proven itself to be a tough
competitor in the arena. SV
MANUFACTURING:
Free Strength
Fighting robots need to be strong.
They also have to fit within a
weight limit. This leads to a trade-off
between building something
capable of taking the forces we
impose upon them and the amount
of weight we have available for
structures. Using more exotic
materials gives us a higher strength
for the weight. Titanium, aluminium,
and magnesium alloys are very
useful in giving improved strength
to weight ratios. These materials are
more expensive than heavier
options. These statements form the
well-used hypothesis of the “
trade-off triangle” of weight, strength,
The red tension forces and blue compression
forces are directly opposite and reduce
towards the center, where they actually
become zero as they reverse direction.
The length of the arrow denotes the
magnitude of the force.
● by James Baker
and cost. The principle of this
triangle is that the value inside the
triangle makes the equation weight
x cost = strength, so if weight = 5,
cost = 5, and strength = 10, to
reduce weight, we must either
increase cost or reduce strength.
Likewise, to reduce cost, we must
either reduce strength or increase
weight, or both. This triangle does
not compromise and until a material
is invented that is light, strong,
and cheap (cheap to produce and
fabricate), most things can be
approximated by this principle.
Thinking Outside
the Triangle
Strength is a constant; a material
of certain thickness has a set
strength value. However, we can do
many things to improve this strength
value. By understanding the forces
we are asking our machines to deal
with — their magnitude, direction,
and duration — we can optimize the
structures involved to get the best
possible strength to weight.
One very simple example is that
a material under bending load has
the largest forces acting upon its
outer surfaces. One surface will be
in tension (stretching), the other in
compression (squeezing). These
forces reduce as you move deeper
into the material, to the point that
they actually become zero at half
thickness. So, do you need equal
strength throughout the material?
If you look at an ‘I’ section
beam, it illustrates this principle
perfectly, where all of the strength
is in the top and bottom section. It
is very important to realize that the
strength in a material increases by
the square of its thickness. So, a
two inch tall bar is four times as
strong as a one inch bar of the same
length and width. By using a two
inch bar with material removed from
its middle (making it the same weight
as the solid one inch bar), we have
increased overall strength by approximately four times (there will be some
loss in strength over a solid bar),
without increasing weight. If you
repeat this process on a four inch bar
28 SERVO 09.2008
