Drive System/Frame questions

[Andrew Schreiber]

Originally Posted by Taylor

So how would one show this on the bill of materials? Are inidividual prices given for the side rails or ladder bars? I can't find that information on the website.

-edit- nevermind. I was one click away. I'm surprised the kit price is the same as the sum of the individual part prices.

Yes they are http://www.team221.com/viewproduct.php?id=95 and http://www.team221.com/viewproduct.php?id=96

[Grim Tuesday]

Thanks for the help everyone! Lots of interesting info here. I checked, and for reference, our current frame is ~60 lbs, including motors, and supershifters, but not electronics, or anything else. Youch.

I have a couple questions remaining:

-On the subject of Nanotubes, they seem to work pretty well. Am I correct in thinking that the middle wheel is driven by only one of the motors? If so, then wouldn't the speeds between the directly driven one, and the one driving the center one vary? Also, why are they only 31" when the robot can be up to 38?

-On the subject of IFI wheels: What size do most teams use, and why? What is better, the ones from IFI, or the ones from Andymark (non sequiter, IFI wheels from andymark, I get it)

So far, this frame seems quite good; have you guys had any durability problems with just the tubing? (I assume it's 1/8 inch? Or is it 1/16?)

Finally, we do have welding capabilities, as well as CNC in-school. If you want to see what this year's robot looked like, take a look in my signature. If the video isn't long enough, here are the stats:

Bottom from T-Slot, the top from 1/16 tubing (21 lbs)
Supershifters and 4 CIMS (20 lbs)
Tank Treads (20 lbs)

[Jared Russell]

You have multiple options with the Nanotubes...

1. Each of the three wheel mounting locations has all of the necessary holes to install a ToughBox Nano gearset. This means you can very easily install a motor to directly drive the center wheel (I would recommend it - that way if a chain fails, your "most important" wheel is still powered). This also means that you may do a 6-motor drive if you want to.

2. One of the Nanotubes comes with a set of spur gears to transfer power between one pair of wheels, and you can add chain to transfer power from the middle to the other end.

3. If you purchase one of these (or the Hex equivalent), you can cut it to length and replace the standard axle. This allows you to use two sets of chain, as well as wider wheels if you desire, to create a more conventional all-three-wheels-connected-by-chain 6WD drive module. This is what we did in 2011, using 4" diameter, 2" wide IFI wheels with blue nitrile tread. Just note that you may need to think about chain tension in this configuration (we actually simply used high-quality #25 chain, and had spare runs ready to install in case of damage or stretch. Despite some HARD driving through two regionals and the Championship, the chain never stretched to an unacceptable level).

[Chris is me]

You already have 90% of the Kitbot on Steroids parts. Try it!

[Hawiian Cadder]

As far as wheels go, we have used both 8 and 6 inch wheels recently, and we have some examples of older robots with 4 inch wheels around our shop. I really loved the 6 inch plasticion wheels that we used this year, they were light, durable, and Grippy. I don't think that any of the plastic or omni wheels from andy mark are very good in the 4 inch size when used with dead axles, the rim around the bolt circle makes it difficult to keep the wheel + sprocket assembly compact in a dead axle system. If you are using live axles and have an effective method for driving them, then as small as you can go is fine.