Thread: Mecanum or 6WD
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Unread 09-01-2011, 23:41
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Re: Mecanum or 6WD

Quote:
Originally Posted by pfreivald View Post
...though the lack of a 5th CIM makes Patrick a very sad boy...
A CIM does 340 watts at peak power.

A Fisher-Price from this year does 290 watts at peak power.

There is no reason to liberate a CIM from the drive if your mechanism needs ~300 peak watts of power, since the FP can do it.

The BaneBots RS550 motors do 250 watts, and there are up to FOUR of them. I would never, ever go with less than four motors in the drive, especially because there are FIVE motors that do more than 250+ watts available for mechanisms. So even if you used just TWO you would still have a lot more power than a CIM (or you could use all four and have a ton of power, aprox. 1 kw.)


If you want your mechanism to be fast, make it light. Lighter = less driving power at the same speed, and with the same driving power, you can be faster. We set our goal speed, from ground to top row, to be well under 2 seconds. We know we can do it without removing CIMs from our drivetrain.


Someone mentioned the Fat CIM's in 07. One RS550 motor has about the same output power (in watts) as a Fat CIM. The Fat CIM just provides its power at a higher torque and lower speed.

@Josh Goodman:
Having 4 CIMs in your drivetrain gives you much better acceleration then 2 CIMs to the same speed.


On the thread topic, I prefer a 6wd hands down over a mecanum. I have driven 6wd, 8wd, and our swerve. I prefer the skid-steer 6 wheel and 8 wheel drive handling over the swerve. Why? The control is really simple. It does exactly what I want it to do, and with practice I can do the tasks you assume a 6wd can't easily do much faster than you. (I also had some fun driving a ~40lb test chassis at about 9 ft/sec, and pushing Jim Zondag across the carpet with it)


Final though (sorry about the long post):
To all of you who say a 6wd can't line up:
http://thebluealliance.net/tbatv/match/2007new_qf1m1
Watch starting at about 00:50 or so. We score through another team while they are trying to block us and score at the same time.
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