FIRST Naming Standard

#1

After my recent post, Mecanum vs Poor Man’s Mecanum, I realised that we don’t have a good naming standard.

Our naming situation is essentially “you say ‘tomato’, I say ‘what is that?’”.

Now, we as a community have 3 choices; live with the confusion, create a standard, or create a thesaurus/dictionary.

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#2

Chaos and Confusion!

But an FRC glossary might be a nice thing. Especially as a reference I can give to new students. If I had a piece of cheese cake for the number of times I’ve explained the term “cheese cake” I’d probably hate cheese cake. And that’s saying something because cheese cake is wonderful!

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#3

I agree!

For drivetrains, I propose we call any tank/west coast variants tanky bois and any drivetrains that move sideways strafey bois.

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#4

How about set up a public form so we can all add definitions and build a dictionary/guide of some sort.

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#5

Relevant XKCD:
image

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#6

I think Discourse has a feature for making “Wiki Posts” that can be edited and maintained. I’m sure if someone wanted to take the initiative they could start such a thing right here on Chief.

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#7

People called crab drives swerve drives at one point, and eventually the community converged.

Somebody called calculated contributions OPR at one point, and the community converged on that.

Similar stuff happened with pink arms, Martian drive, forklift drive, kiwi drive, west coast drive, butterfly drive, octocanum, etc. It’s impossible make a standard and enforce it in the open community we have—something will just catch on.

#8

Was thinking about it when making the post

#9

So a dictionary/thesaurus might work.

#10

If I could figure it out I’d be creating, but I also haven’t taken the time to figure it out yet. Maybe I’ll look this weekend.

The FRC Anthology also exists and might fit a “dictionary” idea.

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#11

There is actually a difference between crab and swerve.

OPR is a subset of calculated contributions, the others that are sort of commonly used being DPR and CCWM.

WCD is a relatively specific type of tank drive.

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#12

We’ve already got a CD dictionary.

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#13

After some investigating into doing something like this, there’s a “Wiki” on the fandom wiki pages, under first-robotics.fandom.com. It doesn’t have much stuff on it, and I have no idea when it was last edited. Although this would be a great place to start adding stuff like that “Devils Dictionary”, or video tutorials, or diagrams on everything from using machinery to pneumatic operation, to programming .
It’s signed by Team 2636 Rebellion, and I for one would love to help out with it.

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#14

That’s satirical though

#15

Fooled me.

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#16

This is a problem likely best solved with a true wiki, not the discourse wiki tag. As a first cut (for drive trains), let me toss out:

  • Skid-steer: the most common FRC drive train, consisting of two independent, parallel drive trains in which multiple wheels are mecanically linked to rotate at the same (or nearly the same) speed. This includes all versions of the KoP and “West Coast” drive trains. Recent versions of wpilib refer to this as “differential drive”.
  • Tank Drive:
    1. A synonym for skid-steer.
    1. A driver interface using two joysticks commonly used for skid-steer where separate joysticks control each drive train, contrasted with “Arcade Drive” and “Halo Drive”. There may be cases where this driver interface is used with other physical drive trains.
    1. A tank-treaded drive train.
  • Arcade Drive: A driver interface (usually for skid-steer, but sometimes for holonomic/swerve drive with a separate rotation control) using one two-directional joystick. In this mode, the y (forward) controls the sum of the two drive speeds, and the x (lateral) controls the signed difference of the two drive speeds.
  • Halo Drive: The same as Arcade drive, but with the X and Y controls being on different physical joysticks.
  • Holonomic: A drive train which supports translation in any direction and rotation of the platform chassis at all times. Sometimes, this term is used to refer to fixed-axle (non-swerve) holonomic drive trains. It is also used to describe wheels designed to support holonomic drive, including omni, mecanum, and ball drives.
  • Killough: a fixed-axle holonomic drive train based on 3 or 4 wheels, either omni wheels, or balls diven by wheels. Three wheel Killough (3WK), where the wheel axes are 120 degrees apart from each other, is also known as kiwi drive. Four wheel Killough (4WK), where the wheel axes are 90 degrees apart (typically at 45, 135, 225, and 315 relative to the robot “front”) is also known as poor man’s mecanum (PMM).
  • Omni wheels: Wheels which include rollers around the periphery which enable the wheels to provide traction force perpendicular to the drive axle, but which are free in the axial (scrub) direction.
  • Omni drive: A drive train which includes omni wheels or other holonomic wheels, most commonly used as a synonym for omni tank, but occasionally used for “H-drive”.
  • Omni tank: A drive train with four (or occasionally 6 or other 2n) holonomic wheels which is essentially a skid-steer drive train with all omni wheels.
  • H-drive (also known as Slide Drive): A drive train which combines an omni tank drive with one or more omni or other holonomic wheels enabling strafing (that is, travel in the direction perpendicular to the tank drive axis).
  • Slide drive: synonym for H-drive
  • Strafe/strafing: motion in the horizontal direction perpendicular to the normal “front/back” of a chassis.
  • Mecanum: A holonomic drive system featuring rollers oriented 45 degrees relative to the axis of rotation. By utilizing two “left” and two “right” wheels, it is possible to implement holonomic drive using four wheels with parallel axes. To enable rotation of the chassis, when viewed from above, the roller axes should form an “X”, when viewed from below, the roller axes should form a diamond shape.
  • Swerve Drive: a drive system in which all wheels (or wheel modules) are independently steerable and independently provided a drive power/speed. “Unicorn swerve” is an older term referring to a swerve system in which there is no effective limit to the number of rotations of each swerve module, either due to clever gearing or slip rings. Most modern swerve systems now merit the “unicorn” designation. Traditionally, swerve drives had one motor controlling the wheel drive, and another controlling steering. “Differential Swerve” drives have two “equivalent” motors, with the sum of the motor speeds controlling the wheel drive, and the difference of the motor speeds controlling the wheel orientation.
  • Crab Drive: A drive system in which all wheels are steerable, but linked such that all point in the same direction. Typically, all wheels are driven from the same drive train as well. This enables the robot to translate in any direction with full traction, but does not enable rotation of the robot. The archtypical implementation of this is “Tumbleweed”. (left as a search term for the student).
  • Articulated Drive: A drive train system which pushes an alternate set of wheels down to enable different drive train characteristics. The difference may include direction, speed, and/or control system. Examples include: lobster, butterfly, and octanum.
  • Lobster Drive: an articulated drive system in which the “alternate” wheels operate in a direction perpendicular to the primary wheels.
  • Octanum Drive: an articulated drive system in which one set of wheels is a traction/skid-steer drive train, and the other set of wheels is a mecanum drive train. Note that it is not at all unusual for the two drive trains to have different effective gear ratios.
  • Butterfly Drive: an articulated drive system in which one set of wheels is a traction/skid-steer drive train, and the other set of wheels is an “omni tank” drive train. Note that it is not at all unusual for the two drive trains to have different effective gear ratios.
  • West Coast Drive: a skid-steer drive train typically featuring cantilevered axes (that is, no support at the ends), direct drive of one pair of wheels (most commonly the center pair), and 2"x1" chassis tubing.
  • Differential Drive: see skid-steer
  • Linkage Drive: a drive train featuring wheels (some or all of) whose axles may be rotated in unison/mirror mode. This designation includes Ackerman Drive (similar to most current automobiles), Fire Truck Drive (similar to Ackerman, but the front and rear wheels remain parallel), and “X drive” in which the left front and right rear wheels rotate together, and the right front and left rear wheels rotate in the same amount in the opposite direction.
  • Ackerman Drive: Two wheels fixed, two wheels (both front, or less likely both rear) rotate together, much like an automobile.
  • Fire Truck Drive: Similar to Ackerman drive, but the “rear” wheels rotate the same direction as the front wheels, allowing the robot to “drift” left or right as it travels forward.
  • X-drive: A linkage drive which allows driving forward, strafing, or efficient rotation through rotating the left-front and right-rear wheels one direction, and the right-front and left-rear wheels the opposite direction.
  • Cheesy (or Cheezy) Drive: a user interface which is similar to Halo or arcade drive, but which scales the left/right differential axis inversely to the robot’s speed.
  • Pakuni Drive: (my invention, never used competitively as far as I know): Similar to a PMM (Poor Man’s Mecanum), but with the wheels toed in somewhat less than 45 degrees (e.g. 22.5 degrees). This allows holonomic movement, but greater acceleration in one direction (forward/reverse) and greater free speed in the transverse (left/right) direction.
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#17

Still want to try building a pakuni drive base. Maybe I’ll convince my team for an off season project

#18

If anyone else wants to read through the FIRST devil’s dictionary, here it is again but now in alphabetical order

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#19

If one more team I’m scouting in Philly calls their kitbot/mecanum drivetrain a West Coast Drive I’m moving back to LA.

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#20

Just move back to LA anyways.

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