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#41




Re: 4194B Drivetrain (Differential, Planetary, Pneumatics)
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#43




Re: 4194B Drivetrain (Differential, Planetary, Pneumatics)
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//Andrew EDIT: P.S. Just because you don't see it doesn't make you an idiot... 
#44




Re: 4194B Drivetrain (Differential, Planetary, Pneumatics)
Yeah I know, as soon as I see it I'm sure I'll understand totally... Maybe I'll try to build one this week, if I find some free time from our 20 motor dragster.

#45




Re: 4194B Drivetrain (Differential, Planetary, Pneumatics)
Ok, so this is looking pretty slick and completely doable. The only disadvantage to this I've seen is the inability to use mecanum wheels.
I'm thinking I'm getting the jist of how it works as well, although I'm with snowpenguin in the fact that I'm going to need to make one. My only question is how do you calculate the different gear ratios? 
#46




Re: 4194B Drivetrain (Differential, Planetary, Pneumatics)
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1. If you have an 8 motor drive, using 2 motors per wheel, then have a pneumatic lift, and 2 motors on the intake, it could work. 2. To find gear ratios, say you want a 1:7 gear ratio on your lift. So you basically have to find your gears, so you get a 12 tooth gear, which is on the motor axle, and then you get the biggest gear, an 84 tooth gear. To find the ratio basically you have to divide 84 by 12, and then you get 7. Also it means that the 84 tooth gear rotates once when the 12 tooth gear rotates 7 times 
#47




Re: 4194B Drivetrain (Differential, Planetary, Pneumatics)
You can use mechanum wheels with only 2 planetarys and a 4 motor drive...

#49




Re: 4194B Drivetrain (Differential, Planetary, Pneumatics)
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The gear shifting part is based on differentials. If you have seen vex differentials before this will be easier than if you haven't, but basically how they work is when you turn the housing, both of the output shafts will turn. However, if you hold one of the output shafts, then the other output shaft will continue to turn (at twice the speed). The way this works in the drive train is that you can use pneumatics to lock the arm output shaft, and the drive base will be the only thing turning. Or you can lock the drive base output shaft, and only the arm will move. Now to the planetary gears. The easiest way to explain these is to imagine a gear sandwiched vertically between two horizontal parallel rack gears (the flat gearlike things that you use to turn horizontal movement into linear movement), one above and one below the gear. Now imagine you have an axle through the gear and are holding the rack on top. If you move the gear and the top rack linearly at the same speed and in the same direction (so the gear doesn't turn), the lower rack will also move in that direction at the same speed. But here's the good part: if you move the top rack and the gear at the same speed but in differ ent directions, so that the gear is turning, the bottom rack will move in the same direction as the gear, but twice as quickly. Now fold this sandwich of rackgearrack into a circle, with your lower rack towards the interior of the circle, and you have yourself a planetary gearset (you'll want to add some more gears (called the planets) around the circle so the center gear (called the sun gear) maintains spacing from the ring gear, the outer insideout gear). The two inputs to this setup would be the top rack (the ring gear) and the gears (the planets). So that's how their differentials and planetary gears work. Ask any more questions you have. 
#50




Re: 4194B Drivetrain (Differential, Planetary, Pneumatics)
An 8 motor drive might be the only possible drive base for teams that wish to pick up 30+ pounds of game objects.
