Beta uses chain drive to
power its electric hammer.
tion when building your bot.
Car vs. Tank Steering
Most robots use tank steering,
which is where each side of the
drive system can go forward or
backward independently allowing
the robot to go forward, backward,
or turn in place. Car steering works
just the way it sounds. The robot
will drive like a large, metal remote-controlled car. One common point
of confusion in tank steering is
turning while reversing. With the
way tank steering works, when
you’re turning left from standing
still, the right side wheels are going
forward and the left side wheels are
going backward. When you’re
turning left while moving forward,
the right side wheels are spinning
faster than the left side in the
forward direction. When going in
reverse, however, the left wheels are
spinning faster backwards than the
right, causing it to rotate to the left
while moving to the right.
External vs. Internal
Wheels
Internal wheels are better
Checkmate uses a strong baseplate
for component mounting.
protected and able to be supported
on both sides. External wheels will
prevent the robot from being hung
up on a competitor’s armor if it
gets lifted off the ground. External
wheels can be hit easily by the
opposing robot’s weapons and
are subject to many more direct
impacts. Which option is best
depends on both the design of the
robot and which features are most
important to it.
Belts, Chains, and
Gears
You’ve got to get the power
from your motors to your wheels
and weapons somehow. Belts,
chains, and gears are your three
options if the motor can’t have the
wheel or weapon attached directly
to it.
Belts are fairly lightweight and
can transmit power over large gaps.
There are multiple types of belts to
choose from but most use tension
and friction to provide enough grip
on the pulleys on each side of the
system to transmit power.
Chains are stronger and heavier
than belts, but serve essentially
the same function as belts. They
Grue uses
tank style
steering to
maneuver in
the arena.
Sewer Snake has external wheels.
Crocbot uses car
style steering to
maneuver in the
arena.
transmit power from one shaft to
another over a gap. Chains need to
be aligned more precisely than belts
due to their inflexibility. If they are
not aligned well, the chain is likely
to fall off or break.
Gears require the highest
precision of the three options and
are also able to be the most
efficient. They are not, however,
able to span the same distances
that belts or chains can. Tight tolerances and proper pitch selection
can result in a nearly indestructible
power transfer system, however, if
the pitch is too small or the gears
are too loose or tight, you’re just
asking for catastrophic failure.
Chassis
At the core of every competitive
robot is a strong chassis. It doesn’t
matter how powerful your spinning
weapon is or how high your arm
can flip other robots if the chassis
can’t handle the forces that act on
it both internally and externally. A
small number of construction
methods make up the majority of
combat robot chassis today.
The first method is to use
square, tubular, or right angle metal
Stewie has an aluminum
unibody chassis.
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