Rookie team drive tream idea

[Solace]

Originally Posted by maxlobovsky

I'm sorry, i confused the Skyway with the new 12" pneumatics they are giving us. I guess that means we need to trade out two of 'em for lower traction ones.

I don't understand how bots have such a huge range in power in their drive trains. I believe FIRST suggests a simple drive train with the Fischer-Price yet some teams, like you, will have nearly quadruple that power. What do we really need?

Yes, I would hesitate to use 4 pneumatic wheels with a two motor drive train. You will most likely have some difficulty in turning. 2 pneumatic and 2 normal skyway wheels will hopefully allow you to turn enough.

I think that FIRST suggests a simple drive train for the rookie teams, as they are often not very experienced in what they are doing (hence the name rookie). Veterans like us have had the opportunity to go around and see what works and what doesn't, so we are much more likely to pull off a more complicated drive train.

Having quadruple the power gives you lots more speed and power in tight situations. It's nice, but NOT completely necessary. Even at a slower speed, if you're robot is pulling 8 ft/sec, you will be able to compete competetively against the majority of other teams. As a rookie team, its nice to see you trying something a little more challenging. Just be careful not to set your sights too high.

Personally, I would stick with the drill motors. Though a little bit more difficult to work with, they do give you a bit more power then the chips would. You can usually take care of any possible overheating problems with one or two well placed muffin fans, something that is really not all that difficult. With 4 wheel drive, you will experiece enough side friction so that the asymetrical aspects of the drill motors will be all but imperceptible. I wouldn't use the exact transmission system that FIRST gives you with the kit (as its just a bit too slow for my tastes), but its a good place to start. Gearing the drills to 7 or 8 ft/sec will probably work out just fine.

If you still want an extra challenge, you can experiment with using a servo or a small pneumatic cylinder to switch between the built-in gears on the drill motor transmission itself. This gives you a whole range of extra options.

In the end, there is no right answer. While more power and speed is always better, I've seen too many rookie teams lose all hope of being competitive because they set their sights too high and attempted something that was beyond their ability. You have to determine what you're capable of before diving into the really tricky stuff.

[Cory]

Originally Posted by Solace

With 4 wheel drive, you will experiece enough side friction so that the asymetrical aspects of the drill motors will be all but imperceptible.

I beg to differ. I can tell you, as will many other teams, it is hardly imperceptible. In 2002, we had to angle our robot a good distance to the side of the goals, just so that when we got to them, we would have drifted enough to be kind of straight. Last year, the robot never went straight either. Im not talking about slow drifting, Im talking about pretty sharp movement. Sure, you can correct it in programming, but coming from a driver, if you dont, its extremely annoying.

Cory

[Eric Bareiss]

Wow, you guys are all over the place with your answers.

I would say Yes to all of the original questions except the gearbox question. I would reccomend that a newer team with little machining help or expertise not try to build a gearbox from scratch. If you are deadset on using the Chips, try to keep it as simple as possible.

As for traction I can't imagine having too much traction with these new wheels. You should be able to turn just fine and go up the step without too much trouble.

[Max Lobovsky]

Originally Posted by Eric Bareiss

Wow, you guys are all over the place with your answers.

I would say Yes to all of the original questions except the gearbox question. I would reccomend that a newer team with little machining help or expertise not try to build a gearbox from scratch. If you are deadset on using the Chips, try to keep it as simple as possible.

As for traction I can't imagine having too much traction with these new wheels. You should be able to turn just fine and go up the step without too much trouble.

It's very tempting to go with your suggestion; it was the only one that gave me a complete answer .

That still leaves me with a question, if we shouldn't build the gearbox, where should we get one?

[Max Lobovsky]

If there are any other Rookies out there following this, here is a very pertinent paper about being able to turn with tank style turning:

http://www.chiefdelphi.com/forums/pa...le&paperid=222

Based on this paper, I think maybe some friction tests (in both directions) of these 12 inch wheels are in order

[Eric Bareiss]

As for using a gearbox, my suggestion would be to use the one that comes in the kit. I haven't seen the one from this year, but I know the one from last year could be retrofitted for use with chips.

I'm not saying that making a gearbox is totally out of the question. You can surely do it with a drill press if you had to. I would get a good idea of what you think you are capable of and work from there.

My suggestion to you is to find a veteran team who would be willing sit down with you for a day and help you work out some plans for a gear box, maybe even help you machine it. It looks like team 25 is only about 15 miles away from you, I'm sure they would be willing to help.