Long-time readers of SERVO Magazine know that he best robot historical information in the industry can be found in Tom Carroll’s monthly column, Then & Now. Each month is packed with
little known facts and bits of robot trivia that help to
enlighten you about the starts, stops, and sputters dotting
the landscape that robots have traveled over the last 97
years of existence.
And so it was in the March 2017 issue when a small
blurb about a German tracked mine robot used during
World War II caught my eye. Named Goliath, this five foot
long tracked vehicle was controlled via a simple joystick.
Coupling the operator to the Goliath was a three-strand
wire control cable that enabled the mine to be driven
forward and detonate its self-contained high explosive
charge.
AH-HA! That’s what I’ll use to keep those “wascally
wabbits” out of my garden! No, I’m not going to detonate
an explosive charge. Rather, I’m going to use a tracked
robot to scare those varmints outta here.
Granted, most of us have driven robot tanks around
our yards performing various duties, but in the context of
chasing animals away from your property, this is going to
take a different kind of vehicle. First of all, this robot is
going to have to be wirelessly controlled. Running a robot
controlled via a wire cable around the yard is a surefire
recipe for getting tangled up in some brush and making
your motorized weapon more of a spectacle for
entertaining your furry pests rather than chasing them
away.
Second of all, this robot tank is going to have to be
fast-moving enough to make the invading animals feel
threatened. Likewise, if push comes to shove, this tank
must be rugged enough to take a bump or two, as well as
deal out a little push/shove of its own when the chase
turns physical. It could even turn confrontational — one of
my prototypes was clobbered by a black rat snake that
refused to yield any ground to my poor little helpless tank.
It must’ve looked like a mouse or mole to that mean snake.
Finally, our nimble tank can’t get bogged down with a
battery-draining motor system. You could wind up as the
embarrassment of the whole cabbage patch if — during the
pursuit of your prey — the tank’s battery conks out. I can’t
begin to count how many times my prototypes suffered
from being “out of gas” trying to race a lazy raccoon
around the yard. The raccoon always won.
This is where the Goliath robot tank concept comes
into play.
Enter Goliath 3
Returning again to Tom Carroll’s March column, we
learned that the original Goliath weapons were
manufactured in two variants: electric motor powered and
gasoline engine powered. Presuming that these two models
could’ve been sequentially numbered (e.g., Goliath 1 and
Goliath 2), that would make our current robot tank Goliath
3. As such, our new fangled model will have several
exciting features: dual motors, battery power, and — most
importantly — Wi-Fi control. Not just any Wi-Fi control,
however. This Wi-Fi control acts as a node for serving a web
page that can be used for controlling Goliath 3 from a
browser. Finally, we’ll have to add a couple of 3D printed
parts to our tank chassis. The resulting critter chasing tank
will be a “near-scale” interpretation of the original Goliath
tank mine robot.
Well, wouldn’t a commercial motorized tank model kit
work just as well? Actually, a kit is used as a “donor” for
Goliath 3. Basically, only the lower hull, drive wheels, and
treads will be retained from the kit tank. A new top hull will
be created with a 3D printer as shown in Figure 1. This
newly made top hull is where the near-scale interpretation
of an original Goliath tank is derived. Plus, the added
benefit from aping the look of the original tank is the
increased inside capacity of the Goliath 3 for holding the
gearbox, guiding electronics, and battery. You can
download these 3D printer part files from this article’s link.
While any 1/48th scale model tank kit should work for
building a Goliath 3, I used an M60 A1 US Army tank
model manufactured by Academy Plastic Model Company
By Dave Prochnow
SERVO 05.2017 39
Figure 1. Out with the old, in with the new
3D top hull.
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