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View Full Version : What drivetrain style are you using?


Mike Nawrot
25-01-2008, 01:38
I'm curious about the ratios of omni directional to tank drive this year. In the past, tank steering has been the standard for all but a handful of teams. This year's game seems to open a huge door for omni directional drive trains though. So what kind of drive train are you using?

Blue_Mist
25-01-2008, 02:01
So far, the plan is six-wheeled tank, but with the middle set of wheels moved back 3.5 inches since the weight moved back so much for this year's design. Most of the components are on the back half of the robot with the giant trackball in front. We did consider, then tossed out mecanum drive (with regrets) since our apparatus is an elevator after a long history of arms, and the general consensus was try to keep the design to one new element per year.

TheOtherGuy
25-01-2008, 02:11
We planned at first to go with Ackermann, but once we got our previous year's 6WD working with Ackermann controls, we abandoned it for the traditional 6WD. So we have a 6WD that drives like an Ackermann...

=Martin=Taylor=
25-01-2008, 02:57
6 wheels.

This game will involve a great deal of turning and maneuvering to capture track balls.

It isn't as easy as "go straight turn left." :rolleyes:

Graham Donaldson
25-01-2008, 07:49
Our first two years were four-wheels, last year we ventured into the realm of six wheels, and it worked pretty well. THis year, we're going with rear drive wheels and casters in the front. We'll see how it works...

Brandon Holley
25-01-2008, 08:02
Our first two years were four-wheels, last year we ventured into the realm of six wheels, and it worked pretty well. THis year, we're going with rear drive wheels and casters in the front. We'll see how it works...

Yikes, based on my experience, you hit the nail on teh head with 6WD... 2WD w/ casters has never worked out well for me

Qbranch
25-01-2008, 08:10
Dualie traction wheels in the centers, dualie omni wheels on the corners, all driven.

I think a 6wd drivetrain is going to be pretty much the best bet in terms of weight/performance balance, and it's ability to hold on in a tight turn.

-q

Super Serb
25-01-2008, 08:16
we are using a flying saucer...:p

Daniel_LaFleur
25-01-2008, 08:17
4 wheel drive high traction skid steer, driving 36" wide.

Excellent ability to hold our line in a high speed tight turn :D

Should be a fun competition, and I expect a very wide variety of robots there

BigWhiteYeti
25-01-2008, 09:09
Just curious, has anyone had any experience with the holonomic style drive? (four omnis pointed at 45 degree angles to the robot sides) We were considering using it but ended up with standard tank and omnis in the back.

Tapoore
25-01-2008, 09:20
Offset center wheel drive (center wheels pushed 1.5" forward)

The front and rear wheels are just unpowered slip wheels. We have used this setup twice before and it's incredibly maneuverable.

midway78224
25-01-2008, 09:44
we plan to use the a 6wd with the supershifters

Elgin Clock
25-01-2008, 09:52
Walking isn't an option in the poll?? :eek:
Hmmph...

Oh well... guess I will have to go with "Other" in that case.

DarkFlame145
25-01-2008, 09:58
we have 6 points of contact on the ground, the front and middle 2 are 2" IFI wheels and in the back we have ball casters. we should be able to turn really well in take mode.

Aren_Hill
25-01-2008, 10:21
a very similar but yet much improved version of what we had last year.... you get to do the research lol. i'm excited for the improvements

SSMike
25-01-2008, 10:23
6 wheels with tank steering. This should make it easier to push the balls around, if need be, and also simply drive around well.

JesseK
25-01-2008, 10:29
We wanted to do a differential on ours, but alas we're trying so many new things this year we wanted to have a solid backup plan of just "driving around". It would be terrible for all of our new achievements to fail just because we made a mistake in our differential design. For this year, we're sticking with something that reliably works for us, and that's tank drive -- but with 2 omnis (possibly 4 if my CoM calculations were off :o ).

There's always the offseason though.

Enigma's puzzle
25-01-2008, 10:37
mecanum we will se how much menuverability we will really get

1619Aaron
25-01-2008, 10:38
Yikes, based on my experience, you hit the nail on teh head with 6WD... 2WD w/ casters has never worked out well for me

Ditto my friend. In 2005 we had that design. Our robot swung all over the place. You have no finite control.

mastercadman
25-01-2008, 12:22
we are going with omni with 4 wheels at 45 degrees to the sides

Brian J. R.
25-01-2008, 12:38
For our second bot ever, we are attempting a holonomic with casters on the corners to keep it stable when we use our lift. (how can casters keep anything stable one might ask....)

CharlieW.
25-01-2008, 13:09
Team 1189 is using a 6 WD design with the 8 in. Andy Marks performance wheels. We'll be using 4 CIM motors and super shifters to provide power.

Billfred
25-01-2008, 13:16
This year will see the Capitals running an improved version of last year's kitbot 6WD, reasons being:

a) We don't have the tooling or the manpower to get all uber-fancy
b) A judicious application of AndyMark products met our needs,
c) We liked what we saw last year.

Nevets Amstier
25-01-2008, 14:12
I agree with what others said about omni/caster wheels

omni and caster wheels are easy to push around. 6wd tank with AM 2 speeds for the win

Madison
25-01-2008, 14:15
6WD with omniwheels at the corners, as we've been doing for a few years now.

http://www.chiefdelphi.com/media/photos/29748

DarkFlame145
26-01-2008, 08:54
Ditto my friend. In 2005 we had that design. Our robot swung all over the place. You have no finite control.

In 05 we only had 2 drive wheels in the middle and then we had 4 ball casters in the corners, it was a good design imo. We could turn on a dim and it just worked well.

sonicx059
26-01-2008, 09:58
Last year for rack and roll we use 6 wheel drive but our front and rear wheels were omni wheels and our middle were the standard wheels we got. This year the team (14 people 10 of which whoom has never done anything like this before) voted on 4 wheel with two omni in the rear.

reflion
27-01-2008, 01:38
We were going to try rack-and-pinion car style steering, but we figured that since we were so behind schedule we'd go back to tank steering. At least we still have the maneuverability necessary to align with and pick up a trackball...

Just out of curiosity (it's my first year at FIRST), what are the benefits of six-wheel drive train over four-wheel? And what's omni-drive?

EricH
27-01-2008, 01:41
Just out of curiosity (it's my first year at FIRST), what are the benefits of six-wheel drive train over four-wheel? And what's omni-drive?Omni-drive is the ability to go any direction without turning. Two classes are swerve (turn the wheels) and holonomic (non-turning wheels with rollers on them).

6WD vs 4WD is a little harder. 6WD doesn't bounce as much as a 4WD while turning. However, the exact benefits depend on the type of 6WD--dropped center, coplanar, and coplanar (omni-in-the-corners) have their own quirks and disadvantages, but all have their advantages.

Mike Hendricks
27-01-2008, 01:42
We usually go with 6wd, but decided that there wouldn't be enough contact this year to justify the weight.

2wd using Dewalt gearboxes on CIMs - in the center with 6" dia 2" wide IFI traction wheels. Ball transfers on the corners :D Basically a VERY fast modified version of our 2004 drivetrain.

buckles
27-01-2008, 16:08
Similar to years past, RUSH is using a 6-wheel configuration. Unlike last year we have gone down from the 8 in. AndyMarks to the 6 in. Also, instead of using omni-wheels to reduce friction when turning we have placed the center wheels 1/8th in. lower on the chassis.

Tottanka
27-01-2008, 16:30
i think that a simple tank drive is gonna own this year.

Hito Seika
27-01-2008, 16:32
We (teem 1225) are using a front weal drive system with two casters on the back. it werks rely well.