22 SERVO 02.2018
system has proven extremely effective
when built properly.
Some lifters drive the arms with
an electric motor. With that system,
the arm is attached to a rotating
shaft. The shaft has a sprocket or gear
on it which is driven by an electric
motor. These systems require heavy
gear reduction to be effective.
Hydraulic lifting arms have
sometimes been used, but are
uncommon in combat robotics. They
are usually too heavy and slow for
most applications of this nature.
Hydraulics are best suited for systems
that require large amounts of torque
and not much speed.
Lifting arms require a very strong
drive and chassis system to be
effective. If it cannot take the abuse a
more aggressive weapon can deliver
while the lifter is trying to get under
its opponent, it will not be successful.
Flipping robots are essentially
lifters run at much higher speeds.
Flipping robots normally use
pneumatics to power their
arms due to the high flow
rates achievable in
Pneumatics can be used in
any lifting system that can
be operated by an extending
Flipping robots are able
to throw their opponents
into the air, possibly
dislodging vital components
or causing them to land in a
manner that would prevent
them from driving.
normally require more
weight than a lifter, as
more power is needed
to send a robot into the
air than to tip it.
flipping system in
European robots has the
piston attached to a
hinged plate that fires
out of a wedge shaped chassis. The
plate is hinged at the bottom, which
causes the swing of the plate to not
only lift the opponent but toss it away
from the flipper robot.
Another common flipping arm is
hinged at the back of the bot. It
extends to the front, and then bends
down to meet the ground with some
means of getting under another robot
pneumatic piston is
vertically or in a
position that when
the piston has
extension, it will be
This reduces the
loss of force due to
leverage some other
allowing for a very
These flipping arms
tend to throw the
opponent vertically and often spinning
into the air.
Grabbing robots are a variation
of the basic lifter. Grabbing robots use
some sort of device to get a hold of
their opponent which allows them to
manipulate the opposing robot in
ways that other types are not able to.
While some grabbing robots do not
use a lifting mechanism in conjunction
with their grabbing mechanism, the
two work together well.
Most arenas used today do not
have dangerous hazards in them, but
grabbers could still be used to remove
your opponent from a match by
putting them over an arena barrier or
into a pit.
Grabbers are a good option
against many opponents in the right
arena. They do have one major
weakness, however. If they face a
robot with a spinning weapon
mounted in an area the grabber tries
to pass through, there is a very good
chance that their grabbing mechanism
will be forcefully removed from the
rest of the robot, making its primary
mode of combat inoperable.
Crushing weapons can be very
devastating when used properly. They
aren’t nearly as common as spinning
or flipping weapons, but are on par
Crusher. Photo courtesy
of Josh Zimmerman.
Flipper. Photo courtesy of Will Thomas.
Grabber. Photo courtesy of Charles Guan.