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Unread 19-12-2013, 15:26
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JamesCH95 JamesCH95 is offline
Hardcore Dork
AKA: JCH
FRC #0095 (The Grasshoppers)
Team Role: Engineer
 
Join Date: Dec 2004
Rookie Year: 2001
Location: Enfield, NH
Posts: 1,830
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95's Pre-season drive base done!

... well, at least mechanically.

Basic 'drive pods' as we call them:



Nothing too exotic about it. Two VexPro ball shifters, #25 chain drive, dead axle, 6in colson wheels, standardized 10-32 hardware as much as practical. We also tried to use as many OTS parts as possible, like the hex standoffs, dead axles, sprockets, and a few other little bits.

The side plates on the drive pods were all cut out on our CNC plasma cutter. "Just wing'in it" our tolerances were garbage... typically -0.03in. With a good setup, fine-cut consumables, and a little more experience we were landing between +/- 0.010 and 0.005in tolerance.

Two of the drive plates were cut out completely on the plasma cutter, then cleaned up by hand. Two were profiled by the CNC plasma cutter and then all of the holes and slots were milled by a proto-trak CNC knee mill. All things considered it was about the same total time to do both, but the milled parts came out a little nicer. Still though, if you gotta knock out a lot of parts, it's REALLY hard to beat 100ipm single pass to cut out 1/8in aluminum plate.

A little tethered driving:



Our most ambitious pre-season project yet, and it turned out pretty well. The ultimate goal, which is still in-process, is to have PID drive control with automatic shifting.
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Maturity is knowing you were an idiot, common sense is trying to not be an idiot, wisdom is knowing that you will still be an idiot.