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Unread 04-04-2012, 12:12
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Simplicity is Complicated!
AKA: Bryan Culver
FRC #0033 (The Killer Bees)
Team Role: Alumni
 
Join Date: Jan 2010
Rookie Year: 2009
Location: Kettering/Greenville
Posts: 707
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Re: Moment of inertia and turning performance

Quote:
Originally Posted by icyplanetnhc View Post
Yes, our 8WD drive from last year worked well for the most part. It had difficulty in an off-season game because the softer carpet allowed our front and rear wheels to make contact with the ground. We tried to alleviate that problem this year by increasing the drop of our center wheel.

With regards to method of using a 6WD as a short-base 4WD with 2 additional wheels, this is something that we've considered last year, but I believe we chose against it because it might've made aiming on one side of the robot, either the scoring grid or minibot tower, difficult (this was before we chose to use "alignment legs" at the bottom of the robot). In addition, if our robot's turning axis is biased to one side, other robots may have a large moment arm to turn our robot.
Drop definatly is a huge part of the equation. Too much and you rock back and forth, to little and the wheel scrub makes it difficult to turn. This is again why tortional stiffness is SO important. With a flexable chassis you end up with dropped wheels while turning and raised wheels when your not: the worst of both worlds.

As to not wanting to be turned sideways, it seems to be mostly a non-issue compaired to the performance gains, you don't notice the powerhouse teams that use 6-8wds year after year getting pushed around very much. (and when you think about having the CoG on top of the middle wheels in the 6wd wouldn't having a changing point of rotation actually make it harder to line up to something?)

Interesting thread
Bryan
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