VEX Drive Trains
J.M. Gabrielse
Drive Trains
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Vocabulary
Four Wheel / Six Wheel
Skid Steering (Tank Drive)
Swerve (Crab) Drive
Holonomic (Omni) Drive
X Drive
H Drive & U Drive
Mecanum Drive
2 Speed Transmission
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Drive Train
A robot’s drive train consists of all of the
components used to make the robot move.
– Motors
– Wheels
– Transmissions
(gears / sprocket & chain)
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Motor
VEX 2-Wire Motor 393
• The 2-Wire Motor 393 is the primary actuator used in the VEX Robotics
Design System. Build rotational mechanisms, drive bases, rotational
joints, conveyor belts - anything that spins can be built using the 2-wire
Motor 393.
• Strong, steel internal gears.
• Can be configured into a "high speed" version.
• The 2-Wire Motor 393 does not have an internal motor controller.
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Wheels
5" Wheels
4" High Traction Tire
VEX has the right tire for
any terrain. Here are
different size wheel
diameters (2.75“, 4“, 5")
are available each with a
different tread type;
choose the perfect wheel
for your application.
4" Wheels
2.75" High
Traction Wheels
Intake Rollers
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Omni-Directional Wheels
2.75"
Omni
Directional
Wheel
3.25"
OmniDirectional
Wheel
Omni-Wheels roll forward like
normal wheels, but slide
sideways with almost no
friction (no skidding during
turns). Use these wheels to
make your robot turn smoothly
or build a holonomic drivetrain.
2.75"
Omni
Directional
Wheel
4" OmniDirectional
Wheel
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Special “Wheels”
6" Wheel Leg
Intake Roller
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Gear Types
standard gears
high strength gears
differential
bevel gears
rack & pinion
worm gear
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Sprockets & Chains
Standards Sprockets & Chains
High Strength
Sprockets & Chains
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Four Wheel / Six Wheel
Squarebot (4-wheeldrive)
6-wheeldrive
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n-Wheel Drive
n = how many wheels are connected to motors
• Two wheel drive: two wheels are powered
• Four wheel drive: four wheels are powered
How many motors the robot has doesn’t matter:
• The squarebot has only two motors, but it is
an example of four wheel drive since all four
wheels are connected to motors.
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Squarebot
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Skid Steering
(Tank Drive)
The left and right side of
the robot are
independently powered.
To rotate, one side
goes forward and the
other goes backwards.
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Swerve/Crab Drive
A swerve drive robot has the
ability to rotate its wheels.
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Omni-Directional (Omni) Drive
aka Holonomic Drive
Omni wheels pointing in opposite directions
allow the robot to move in any direction or
spin.
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Omni-Directional (Omni) Drive
aka Holonomic Drive
formation
A drivetrain that can move in any
direction at a given moment, without
waiting for wheels to steer is called
an Omni-Directional Drivetrain. These
drivetrains use special wheels, called
“omni-wheels”. Omni-wheels are
wheels with small rollers around the
perimeter that freely spin perpendicular to the wheel’s
rolling direction. This means that the wheels can slide
sideways with very low friction.
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Omni-Directional (Omni) Drive
aka Holonomic Drive
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Omni-Directional (Omni) Drive
This is a true holonomic drive aka X Drive.
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H Drive & U Drive
Other holonomic drives
Four Wheel Drive
Square Robot
H formation
U formation
Two Wheel Drive
Square Robot
U formation
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Train Drives
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Mecanum Drive
The Mecanum drive is also a holonomic drive.
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Mecanum Holonomic Drive in Action
If video do not play, go to this link:
https://www.youtube.com/watch?v=pP8ajNMx84k
A VEX robot with a holonomic drive.
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2 Speed Transmission Drive
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2 Speed Transmission Drive
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VEX Drive Trains
Thanks!
J.M. Gabrielse