the development of the
robot concept was
refined over and over.
Upgrades and improvements were undertaken,
often pre-emptively. The
original concept of a
simple, low cost robot
was all but gone, and the
highly advanced design
was starting to look like a
30 lb version of a very
successful larger robot.
Hmmm ... this got us thinking. More
upgrades and design changes were
authorized, and the four cheap drill
motors originally planned for the
drive system were replaced with six
Team Whyachi TWR15 gear motors
and wheels.
This, of course, resulted in a
controller upgrade and new
batteries as we planned to over-volt
the motors. Since this well known,
heavier robot was now the basis
for my robot (named Savage), the
owner was contacted and he was
kind enough to offer his blessing.
Now the project continues with
renewed enthusiasm to do
everybody proud. A number of
features in this robot were inspired
by other awesome machines. The
pneumatics system, for example, is
based on a liquid draw CO2 system
as used successfully in many robots
on the British Robot Wars TV show.
My own heavyweight robot ‘Wheely
Big Cheese’ uses an almost identical
concept on a larger scale. I was also
inspired by the old British warship,
HMS Warrior. This ship made
everything else on the water
obsolete when it entered service
in the 1860s.
600 g CO2 bottle, pressure relief valve, dump
valve, 1/2” solenoid valve, and custom-made ram.
The ship’s design feature I was
most interested in using for the
robot was its armored citadel
principle. On HMS Warrior, the
center of the ship — including gun
deck and steam engines — were
enclosed in a thick iron box of
armor — an internal chassis that
formed the core strength of the
entire ship’s structure. The rest
of the ship basically bolted to this
inner box. For Savage, I wanted to
try out this same idea, so I used a
chassis milled from a solid billet of
2L97 aluminium alloy from which
everything would be mounted. To
compliment this high core strength,
the armor covering the robot is 8
mm titanium, with some 4 mm
titanium and 4 mm Hardox 400
wear plate in strategic places. All
the aluminium used for supports,
flipping arm, etc., is the same 2L97
alloy used in the main citadel.
If we think of Savage as a ship,
the upper deck is fully enclosed
within the chassis citadel and houses
the pneumatic system, flipping arm,
batteries, speed controller, and radio
system. Below this (beneath the
waterline, if you will), sit the six
Whyachi gear motors upon which
The test rig with
the planned parts.
Lots of machine work
has gone into every part.
Custom-made ram
for liquid CO2 use.
the robot runs. The titanium armor
extends downwards from the
chassis to the floor, protecting the
motors and wheels.
When designing the flipper,
I wanted to ensure that the
mechanism was mechanically
strong, effective, and an integrated
part of the armor of the robot. The
pneumatic system that powers it
is also very powerful, but I felt I
needed to leave options to upgrade
later. I built a test rig system with a
custom made, aluminium manifold
to allow me to experiment with
different configurations and
components. The ram currently used
is a custom design that was of a
size specifically chosen to allow the
body to be tapped at its base to
1/2” BSP thread. This can then
be screwed directly into the
solenoid valve, negating the need
for fittings.
I tested an identical design
tapped to 3/4” BSP (as the manifold
was made to accept either size)
which was significantly more
Aluminium flipper
arm components.
SERVO 10.2008 23