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Unread 08-06-2014, 13:34
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asid61 asid61 is offline
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AKA: Anand Rajamani
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Re: The in-wheel swerve shifter!

Quote:
Originally Posted by Chris is me View Post
I'm not sure if this would work, but it's an interesting idea. Is there any reason you have only one planet gear? Are the planets going to be carried by anything or are they just floating? Is the planet arm fixed, free spinning?

If you need an initial reduction from the drive motor, why not just shift there?
There are actually 5 planet gears. The way I CAD stuff, I want to put in all the shafts and e-clips before patterning the planet gears 5 times.

So the reduction comes from the sprockets on the wheel and shaft above the wheel. The cim can go directly above the module right in the center of rotation, to remove the need for gears outside the swerve module.

Why can this not be shifted on the fly? Am I missing something here? Keep in mind that this can ony go forward. There is no reverse because I'm driving sun-ring, not sun-carrier in the planetary gearset. This means that the reverse of direction by the cim will only work against the inertia of the drive shaft, not the whole robot.
Here is a good link to learning about planetary gearset ratios: http://science.howstuffworks.com/tra...ment/gear7.htm
As you can see, the ratio between sun and carrier, which is normally used in planetary gearboxes, is (ring/sun + 1):1. However, this uses a sun and ring mate, for which the ratio is -(ring/sun):1. So when the shaft reverses direction, the wheel continues spinning the same direction that it was before.

Last edited by asid61 : 08-06-2014 at 13:37.