Chief Delphi - 3 wheel vs 4 wheel vs 6 wheel

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- - 3 wheel vs 4 wheel vs 6 wheel (http://www.chiefdelphi.com/forums/showthread.php?t=32659)

Re: 3 wheel vs 4 wheel vs 6 wheel

sorry but i'd still like to disagree on that one... i just dont like how the whole robot bounces around while turning on treads. sorry, never was a fan

Re: 3 wheel vs 4 wheel vs 6 wheel

We did a three wheel chassis last year, two powered and a caster. We had no problem with tipping even when we went to raise yourselves up on the center bar.

4WD is good, but 6WD is better, if you have time and resources to pull it off.

Re: 3 wheel vs 4 wheel vs 6 wheel

Quote:

Originally Posted by 663.keith

treads can be very fast and easy to turn if done correctly. We have a robot that is by far the fastest we have built and he uses treads. conversely, one of our 4wd robots was terrible at speed, and could barely turn (it used a wonderful "Bounce turn"). I believe that treads work better than 4 wheels in many cases.

That depends on how you build it, if you drop the center portion of the tread (much like most 6wd designs with their center wheels), then turning on a tread drivetrain can be better than a 4wd platform. But if your treads are just 100% level, then there's a whole lot more side-friction to overcome compared to a 4-wheel drivetrain.
As for speed, that depends on your motors, gearing, and drivetrain efficiency.

We also had that problem with our 2003 robot, where would hop side to side when it would turn. It had too much traction and only weighed like 90 lbs.

Personally, I like 4wd, its a good balence between drive systems. Plus the kitbot is set up to do so.

EDIT: When I read 3wd, I actually thought you meant an actual 3WD robot with only 3 wheels, kinda like a kiwi drive platform. But if you're talking about a 2wd caster bot, I've always had bad experiences with them, but with some modifications, it can be good.

Re: 3 wheel vs 4 wheel vs 6 wheel

6-wheel is the best, but make sure the middle wheel is slightly lower (1/8 ish). This blends the 2wd and 4wd, all your weight is going to wheels with power so you should have good traction. It also centers more wieght on the center, oppose to the edges (farther from the turning point) of 4wd. This means 6wd takes less force to turn the robot. Also the wheel base is shrunk since amost only 4 wheels will be possible to signfigantly press into the ground. 4wd of the same shruken wheelbase are not stable. I saw many tip last year. Hey with 6 wheels, if it has problems, you can throw of wheels until you have 4wd of 2wd with a castor or two. It is easier to take away then add.