around as you follow your wirelessly controlled mini tank.
The Cross the Road system can be controlled over your
smartphone using the uCANDrive app (available for iPhone
and Android). Setting up smartphone control is easy once
you have all of your IP addresses set correctly for the 2CAN
and router — all you have to do is enter the 2CAN IP
address in the app, then change the IP address of your
phone to be on the same subnet. You can map the controls
as any combination of buttons and sliders you like. We
opted to use sliders — one for each side of the tank. There
were also buttons we could map to one of the solenoid
ports on the Canipede RCM. The solenoid port would be
perfect for controlling the cannon of our mini tank.
Maybe Your Best Course Would
be to Tread Lightly
Making a mini tank out of the Agent 390 strikes us as
especially appropriate since continuous tracks were really
pioneered for military applications. A predecessor of
continuous tracks were dreadnaught wheels, which were
basically wheels with feet along the rims. The idea was to
allow heavy loads to move across soft ground without
sinking in — the feet on the rims increased the footprint of
the wheels and more evenly distributed the weight of the
Carriages with dreadnaught wheels were first deployed
in the Crimean War in the 1850s. Development on such so-called “endless railway” wheels continued after the war,
and they were used to successfully carry steam-powered
tractors over soft earth. Soon, inventors were proposing
continuous tracks comprised of jointed segments as an
alternative or improvement on dreadnaught wheels. Early
continuous track designs used as few as eight jointed
segments, and they really weren’t ready for primetime for
the rest of the nineteenth century.
During the Second Boer War at the close of the
century, UK forces did not deploy vehicles with
dreadnaught wheels or continuous tracks, and instead
relied on the lower tech solution of wooden plank roads.
Continuous tracks were refined in the early twentieth
century for use with tractors, and such tractors were used
for hauling artillery in World War I. The prototype of the
modern tank was also developed for World War I. The
Mark I Tank developed by the British Army had a
distinctively rhomboid shape, and also the continuous tracks
that we all associate with modern tanks. The rest, as they
say, is history.
Continuous tracks have many more advantages than
simply avoiding that sinking feeling when traversing soft
ground. As far as large-scale vehicles, continuous tracks
allow for much tighter turning than traditional Ackermann
steering (also known as automotive steering, since it’s what
your car has). That isn’t as much of a factor for smaller
robots, where differential steering is the norm (where both
sides of the drive are independent).
As particularly relevant to our purposes, continuous
tracks provide a great base for designs that need a long
SERVO 04.2016 55
SIZING UP THE ARTILLERY.
FIT FOR A MINI TANK.