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Unread 11-05-2012, 18:44
AlecS AlecS is offline
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Re: 8 Wheel Chassis Design

To go along with what Sean said, why did you chose to go with the SuperShifters, AND an additional sprocket reduction to the wheels?

By looking at the pictures, it appears like you are using a 12-22 sprocket reduction after the SuperShifters. If this is in fact correct, this would yeild,
-With the Standard 2.56:1 Spread,
~2.84 FPS in Low Gear,
~7.27 FPS in High Gear,
and only ~17 Amps per motor to spin the wheels in low gear.
-With the Standard 4:1 Spread,
the same low gear
~11.37 FPS in High Gear.
Using the optional final reduction reduces speed in both cases, though I'm assuming that wasn't your intention.

In either case, you may want to think about reducing your overall reduction. 2.84/7.27 FPS is going to be quite slow for navigating an FRC field (think, FRC71 in 2002), and won't help your overall pushing power, since you're already limited by traction.

If you want to stick with SuperShifters, you will probably want to look into direct driving one wheel, and chaining the other 3, 1:1

Although you may be "sick" of the AM Shifters, using the same (assumed) 12-22 sprocket reduction, they would yield, ~6 and 16 FPS. Both very respectable speeds to maneuver the field, and would still be able to spin the wheels in low gear in under 40 Amps per motor.

The third option would be to make you own gear reductions, and use smaller wheels.

Also, one more note, this drivetrain only has an .SLDASM on frc designs. In order for Assemblies to opened on other machines, both the .SLDASM, and all .SLDPRT files in the assembly need to be present. Using the Pack and Go feature simplfies this task greatly.

-Good Luck
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Alec S.
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Last edited by AlecS : 11-05-2012 at 18:54. Reason: didn't see sean's post.