Embedded Files
The first thing to do on any robot is to build a drive base. There are a few different types of drive bases that are common among VEX students. These are the H drive, X drive, and parallel drive. These can be combined with different types of wheels, such as omni's or Mechanums, for different strengths. They can also have different amounts of motors. First up, we'll look into shapes:
X drive
X drive
X drives get their names from the wheels pointing to make an X in the center. This gives the chassi an octagonal shape. These drives are typically built for quick turning without having to strafe (as with mechanum wheels) or go in a circle, as to rather just spin in place. X drives are only built with Omni wheels.
Pros
Pros
Quick turning in place, which can help for autons
Quick driving forward and backwards
more space for odometry tracking wheels
Can strafe when driving
Reduced "wiggle" or room for error within omni wheels
Cons
Cons
Can be harder to program and control during driving and auton
Spacing between wheels and axels must be absolutely perfect
Can consume space overall
Can be heavier
Examples:
Examples:
32T
29760C
53999F
Parallel Drive
Parallel Drive
Parallel drives are by far the most common type of drive, because they're simple to build and can be used with omnis and mechanums. They're the most versatile size-wise, and are also the easiest to adapt to having more or less motors
Pros
Pros
versatile and easy to change
quick to complete building
works with mechanum wheels
can be almost any size
easiest for unique numbers of motors
Cons
Cons
may need reinforcements to not flex
incredibly common and easy for other teams to copy
not ideal for turns (except for possible mechanum usage)
Examples:
Examples:
9409B
371T
Kepler Electronics
H Drive
H Drive
H drives have become increasingly uncommon over the years as they require an odd number of motors rather than the usual 2 or 4. H drives have one or two extra omni wheels in the center perpendicular to the other wheels to turn on a dime. They're only useable with omni wheels. They typically work best on large chassis. This year, they're much less popular thanks to the common designs that suck balls up the inside of the robot, passing through where the central wheel would typically fit.
Pros
Pros
quicker turning than the average parallel drive
can be a good use of a spare motor
simple to build
easier to code to strafe than using mechanums
Cons
Cons
Takes up important space that change up balls typically travel through
Turning can be achieved other ways
Requires an odd number of drive motors
Examples:
Examples:
School project
375H
Doug Klein
Our recommendation is that beginners start by building a simple parallel drive. It's the easiest to code and build for newbies, and it makes plenty of space to build on top of!
Mechanum VS Omni Wheels
Mechanum VS Omni Wheels
Omni wheels
Omni wheels are good for low friction movement, but cannot "strafe" or move side to side without turning unless they are pointed in an X towards each other with specialty code. These come in many different sizes, but the most common is the 4 inch because of the improved speed.
Mechanum wheels
Mechanum wheels are higher torque and lower speed than the equivalent omni wheels, but their conical rollers allow for them to strafe side to side and spin in place when used on a parallel drive. These wheels have become more prevalent since the widespread introduction of V5 motors.
Page updated
Google Sites
Report abuse