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Unread 30-04-2007, 08:12
Qbranch Qbranch is offline
wow college goes fast.
AKA: Alex
FRC #1024 (Kil-A-Bytes)
Team Role: Alumni
 
Join Date: Apr 2006
Rookie Year: 2006
Location: Indianapolis
Posts: 1,174
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Re: Robot chassis shape

Not so much this year, but last year when we were really having a tough time with weight I ran stress analysis on most everything (especially parts in the shooter itself) as well as the drivetrain (except for the wheels... something i would later regret! ) to see where weight could be taken out...

result: a very lightweight and cool looking frame, plus a shooter assembly total weight of 20lbs

the stress analysis is also a great way to learn the limits of materials you use everyday; like plate aluminum, UHMW, etc. I ended up making the track guides for our '06 bot out of UHMW thanks to the ability to rapidly prototype in the ANSYS stress analysis system... cool stuff.

on the ultimate shape, it seems that for manipulators the triangle always looks to be the best shape ( 2005 bot ) since it allows for the longest arm. Other than our '05 bot we've always had a rectangular frame, boring I know, but easy to work on and build. Thanks to bumpers, one interesting frame option that really helps out in the pits is cantalievered wheels ( example ). bumpers also make it a little more feasable to use a welded frame since you don't have to worry about shock loading on welds as much, so we tried our first welded frame this year ( near complete 2007 bot ).

Still, for our team at least, it seems that rectangular frames for most everything but for heavy lifting the sheet metal triangle works best.

-q
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Electrical Engineer Illini
1024 | Programmer '06, '07, '08 | Driver '08