pic: Ultimate Vex crab drive 2

[cire]

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[Vince lau]

very nice... thats the same thing I'm trying to do

[Jeremiah Johnson]

Awesome! Looks like the same concept we used on our FRC robot this year, just a little more complex. Nice job, some day I'll do something similar-ish.

[cire]

Originally Posted by Budda648

Awesome! Looks like the same concept we used on our FRC robot this year, just a little more complex. Nice job, some day I'll do something similar-ish.

I was inspired by team Robonauts FRC 118 and their 6 motor gearbox. I knew the second I saw it that I wanted to build one. Eventualy I will be inplimenting a 2 or even 3 speed gearbox into the design. Right now it is sort of minimalist because the payload that is suposed to go on it takes up my other 4 motors. I also plan on buying some pots and hooking them up so i can switch between modes such as swerve or crab with code.

[Jeremiah Johnson]

Okay, when you say crab or swerve, what is your definitive difference? I don't quite understand the differentiation.

[cire]

I am not 100% sure but from what ive seen and heard I think that crab is defined by just being able to drive in any direction, Swerve is like driving a car where not all of the wheels are pointing the same direction. So I would be able to push a button and it will just drive like a crab, and all 4 wheels will rotate together - meaning crab drive. Or i can push the other button and it will switch to where it will drive more like a car with only the front wheels rotating. I can also push the other button and it would drive like a tank.

[Brandon Holley]

Originally Posted by cire

I am not 100% sure but from what ive seen and heard I think that crab is defined by just being able to drive in any direction, Swerve is like driving a car where not all of the wheels are pointing the same direction. So I would be able to push a button and it will just drive like a crab, and all 4 wheels will rotate together - meaning crab drive. Or i can push the other button and it will switch to where it will drive more like a car with only the front wheels rotating. I can also push the other button and it would drive like a tank.

i dont believe that is the general definition everyone on delphi goes along with here... http://www.chiefdelphi.com/forums/sh...rab+vs.+swerve
check that guy out, a lot of seasoned veterans comment on what the difference is...essentially theyre the same thing

[artdutra04]

Nice coaxial swerve (or crab) drive!

[cire]

Originally Posted by Brandon Holley

i dont believe that is the general definition everyone on delphi goes along with here... http://www.chiefdelphi.com/forums/sh...rab+vs.+swerve
check that guy out, a lot of seasoned veterans comment on what the difference is...essentially theyre the same thing

I admit I worded badly, below is the definition from that post that makes the most sense to me. I designed my bot to be coaxial swerve, but it is set up as crab drive in the picture because all the wheels are attached.


Definition:
Crab- having all wheels rotate together (ie: locked to the same angle). Derived from the ability of a crab to scuttle in any direction.

Swerve- Either all wheels can independently rotate, or they rotate in sets of two. Allows you to both translate and rotate, as well as drive the robot using ackerman steering, or monster truck steering where the front wheels turn one direction, and the rear in the opposite direction.

[RyanN]

Yay, I have inspiration (FIRST) to build one myself. I always like vex projects and I'm already designing something. Thanks!