2008 and drivetrains

[Tottanka]

So...
what kind of drive trains do you guys suggest this year, and mroe importnatly - why?

I dont tjink high traction is needed this year as there will not be much pushine envolved, The bigger your wheels this year the better it is.

I also dont see an advantage that big for a 6WD on a 4WD.

Right now, we are looking at either a mecanum or holonomic (4 omni wheels at 45 degrees) drivetrain. The big advantage would be the quickness that the robot could turn corners, or I should say strafe. This would thus eliminate the need for turning around the corners

[Joe G.]

Agreed, Mecanums are going to be popping up left and right this year.

[reyray1000]

I would say any drivetrain that includeds either omni or mecanum wheels would be the best idea for a drivetrain this year. the competition is on carpet, so high torque would not be necessary, less traction would be better, if u want to slide which for some teams will be doing that if they decide to build a robot to only drive. for pushing the ball i would suggest mecanum b/c they allow you to keep control of the ball (if u create something to hold the ball). traction is not necessary for this b/c of carpet, so go with omni or mecanum.

[lukevanoort]

Yeah, mecanum, kiwi, four-wheel omni-wheel designs, and swerves are probably going to be the class of the field. That said, my team has decided to do a light, fast, low traction, two-speed 6WD with adjustable centre wheel drop. We figure that practice is the key to this game and getting a fast, working drivebase with potential of some optimization (we intend to find the ideal centre drop) done early will pay dividends come regionals. What good is a omnidirectional design if your drivers don't know how to use it?

[Billfred]

It would be kinda fun to try swerve in this year's game, but our level of sophistication prohibits that. My preference is for an adjusted version of our 2007 robot, Uppercut (photos here), for a few reasons:

a) It's proven to be a heck of a performer as-is
b) Easy and quick to assemble--no real machining required.
c) Can be tuned relatively easily; we can change it from lightning-fast to a more mid-tempo robot with better pushing with a Saturday and a sprocket order.
d) We're just suckers for the kitbot, what can I say?

However, it should be noted that the team has yet to make a decision. We'll see what's up soon.

[roborat]

We are looking at using the two kit wheels on a front wheel drive and omnis on the rear instead of casters. You will have the weight of the ball over the drive wheels if we decide to carry it around before hurdling. We have used this in the past and it turns great. We thought about four omni drive but we have a new driver this year and afraid of lack of practice time to try this.

[Digan]

Seeing as this is the appropriate thread imo.

Why type of drivetrain would I want to use if I wanted to be able to turn fast yet be easy to control.

[Priyadarshy]

most will disagree but i think a traction drive system (six wheel for example) will be a good choice this year, it is going to have a lot of control and not be giving way during all those high speed collisions

[JHSmentor]

Originally Posted by Priyadarshy

most will disagree but i think a traction drive system (six wheel for example) will be a good choice this year, it is going to have a lot of control and not be giving way during all those high speed collisions

I think I agree with you - high traction and speed in the forward motion (this is a fairly straight course when you get down to it) with the ability to make a turn. some manouverability will be needed and some good instincts for driving to see objects ahead of time. 6wd with Omni's in the corners (not mecanums) and traction or kit wheels in the middle.

[pakratt1991]

We are going with the same track system as last year, and with a little SLOWER high speed since our high speed was a tad uncontrollable last year, but I believe (especially in hybrid) it will be nice to tell our robot to go somewhere and be pretty sure it will make it.

[dtengineering]

Remember that "tank drive" robots don't need to turn.... or at least not turn much... they can just go "forward" down one side, then "backwards" down the other, just like mecanums and other omni-drive systems.

I would recommend, however, that teams using mecanums get them finished earlier than usual so that the programmers and drivers can have time to get all the control loops worked out. Building a successful mecanum drive (especially with Banebots gearboxes and AM wheels) is much more of a programming challenge than a mechanical one.

What I am looking forward to is the emergence of "car" steering. We are seriously considering setting up just like a sports car... rear wheel drive, front wheel steering. While it doesn't have a "zero" turn radius like tank drive, it should work great for high speed cornering and swerving around other robots heading down the straights.

But we've got a few other tests to run before we commit to that just yet.

Jason

[artdutra04]

Originally Posted by dtengineering

What I am looking forward to is the emergence of "car" steering. We are seriously considering setting up just like a sports car... rear wheel drive, front wheel steering. While it doesn't have a "zero" turn radius like tank drive, it should work great for high speed cornering and swerving around other robots heading down the straights.

I think this is one of the best years for Ackermann-steering that FIRST has presented in a long time.

[MrForbes]

Originally Posted by dtengineering

What I am looking forward to is the emergence of "car" steering.

Same here, looks like a great opportunity for the car guys to put some knowledge to work

But we'll try out the other two drive trains we have sitting in the shop right now...6wd and mecanum....(the programming for mecanum is really not that difficult, if you use a canned solution...according to my son who made it work pretty easily)

[AdamHeard]

I think teams that quickly jump to mecanum and omni wheeled designs may regret that choice later on.

Yes, FIRST is discouraging defense, but do you really think with 6 robots on the field and 4 40" 10 lb balls there isn't going to be any collisions and interference? Knowing this is probably going to happen, I'd rather be the 6WD bot with nice high traction wheels than a holomonic (guess who is going to be knocked of course more....).

Now, a crab drive is ideal; but we can't all pull it off.

If there was ever a year to call Wildstang's, I think this is it.