Front wheel steering VS. 4WD

[Jeff K.]

Originally Posted by Denman

the only problem with 4 wheel drive is your more likely to get stuck against a wall or something straight...

How can you get stuck against the wall? The only way you could if you intentionally tried to get wedged under something like the arena wall, but that would totally take out the arena wall too...That would be insane.

But o well, I might be wrong.

[Evan Austin]

If you really want a 2wd, you could use two small omni wheels or casters on the front (or rear) of your robot and drive like a normal tank drive. We did this in the past and it did work well, you just don't have as much pushing power as a 4wd would. However, it should be lighter than a 4wd too, and still be fairly maneuverable.
I would not use a car type steering on a robot because of the limited area in which the robot must operate. It could be done, but I think that it is more trouble than it is worth.

[Kelvin Ng]

yeah our team is planning on using 2WD instead of 4WD. If we don't use casters nor car steering, what is a good substitute?

[sanddrag]

Originally Posted by Kelvin Ng

yeah our team is planning on using 2WD instead of 4WD. If we don't use casters nor car steering, what is a good substitute?

I assume you are having four wheels, with two driven. I would suggest making the driven ones really high traction and the non-driven ones fairly low traction.

[jrocket567]

Originally Posted by Kelvin Ng

yeah our team is planning on using 2WD instead of 4WD. If we don't use casters nor car steering, what is a good substitute?

were using 2 driven wheels, and dropping the casters and replacing them with teflon skids..something really slick..
j

[Kelvin Ng]

in response to skids or low friction wheels, how about omniwheels? i found out what they were and how they worked yesterday and i am quite amazed. secondly are those wheels expensive? we don't have any sponsors yet and living off our science department at the moment.

[greencactus3]

Originally Posted by Kelvin Ng

in response to skids or low friction wheels, how about omniwheels? i found out what they were and how they worked yesterday and i am quite amazed. secondly are those wheels expensive? we don't have any sponsors yet and living off our science department at the moment.

yea, they can be slightly expensive. but you can attempt to make your own. well, we havent had much luck in that since we have only a drill press... without a turntable or w/e you call it.. but yea. ball transfers work too. and teflon. nylon maybe? ummm yea, omniwheels are nice...

[Mike33]

If you wanna go 4WD, my team made a 4-speed tranny last year. the CAD drawings should be posted on www.ndprep.org/robotics. With a little coding, we made this into an automatic transmission. 4WD has its plus sides and its minus sides. You have to decide depending on your strategy and/or your tetra manipulator. But I would go for the 4WD. There's gonna be alot of traffic on the feild.

[Eric Yahrmatter]

Originally Posted by Mike33

There's gonna be alot of traffic on the feild.

4 wheel drive, combined with a multiple speed transmission, will supply a robot with enough torque in low gear to push just about anyone. In high gear, you then can have high straight-line speeds, but the turning can be difficult.

[Vash]

If you wanted to get creative with slippery skids you could use something like a half sphere of teflon in place of a castor. Also if you did use two wheels to drive you could replace the wheels to increase traction.

[Bleric]

Yes, chalk up another vote for teflon skids / omniwheels. (For a 2wd robot, that is) Casters DO have a tendancy to make the robot drift to the left or the right.

Besides, omniwheels look SO cool