Subject:
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Re: Non-pivoting free wheels (was Re: odometry (was Re: Homing with the IR Tower)
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 4 Aug 1999 02:12:26 GMT
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Original-From:
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Doug Carlson <dcarlson@net-info.IHATESPAMcom>
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Viewed:
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1762 times
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Here's a couple of short motion clips of the killough platform in motion. (about
1.4 MB each in mpg format)
I had been waiting to get a few really nice movies of this but a relative of mine
dropped by last weekend and shot these to show a
friend of his. If you have never seen one of these in motion you might find them
interesting.
Hope you enjoy them!
http://www.net-info.com/~dcarlson/klw1.mpg high resolution/shorter length
movie
http://www.net-info.com/~dcarlson/klw2.mpg low resolution/longer length movie
with several different motions
-- doug (who's wishing he had more time to work on this stuff)
Robert Munafo wrote:
> You'll have a very hard time making a ball-and-socket design bear a load and
> turn without lots of friction. Putting wheels between the ball and the socket
> just brings us back to the problem that we were trying to avoid by not having
> wheels.
>
> A much better solution that will definitely accomplish what you want is 1/3 of
> a Killough platform. This is a pair of balloon tires that are free to rotate on
> two axes (via a rotating mount) and geared to each other so that the primary
> axles of the two wheels are always at a right angle, but coplanar. Here are two
> good pictures of the design:
>
> http://www.net-info.com/~dcarlson/images/kmrp3.jpg
>
> http://carol.wins.uva.nl/~leo/lego/killough.html
>
> There are two balloon tires, and only one touches the ground. You'll have to
> omit the motor in your model so the wheels turn freely on both axes.
>
> I also want to point out that the full Killough platform with three pairs of
> wheels is also rather nice for many other reasons, the main one being that you
> can move in any direction without turning, or in fact you can turn while moving
> without changing your direction of movement. This makes for much better
> maneuverability and flexibility and is also pretty darn fun to watch. However,
> it wouldn't be that great for odometry because it's difficult to travel in a
> perfectly straight line.
>
> - Robert Munafo
>
> In lugnet.robotics, Erik Steffl writes:
> > [...]
> > it looks like the good free wheel should do its 'wheeling' equally
> > well in each direction. therefore it should be a ball. the design should
> > look like this:
> > [...]
> > there should be something between the holder and the ball so that the
> > ball can rotate freely (few wheels would do the trick).
> >
> > if did was not clear enough - it is something like a computer mouse
> > ball, only it is supported, not hanging (so it is where the mouse ball
> > is but it is of the same construction as trackball ball).
> > [...]
> --
> Did you check the web site first?: http://www.crynwr.com/lego-robotics
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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