Alt-BEAM Archive
Message #05654
To: beam@sgiblab.sgi.com
From: Sean Rigter rigter@cafe.net
Date: Wed, 11 Aug 1999 20:11:09 -0700
Subject: [alt-beam] Re: "Linear Wheels" (was: LEM videos now on-line)
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Now that's a unique motion and just what I hoped for! I would love to hook up a
complex sensor layer and see it riding that horse!
It seems to me that a conceptually simpler "linear wheel" would, as shown on
attached example, consist of a 10 (or more, or less) segmented circumference
wheel with a "free wheeling" spindle on each segment. The curvature of each spindle
is equal to the arc segment between each of the spokes to form a near perfect
circlular wheel. The Killough Lego version can be seen to consist of 6 wheels ,
each a flattened spherical spindle, with pairs of wheels driven in tandem 90 degree
out of phase. As a result of that "single spindle" arrangement, the wheels have to
reverse rotation every half cycle which incurs some energy loss which would not be
present in multple spindle segmented wheels. I was surprised how smooth the motion
of the Killough platform looked on the video. I expected to see some bumpiness but
the spherical wheel shape seems to take care of that.
regards
wilf
"John A. deVries II" wrote:
> This might have no bearing (pardon the pun) on what you are talking about,
> Sean, but I strongly suggest that you take a look at a two
> degree-of-freedom "linear wheels". They are more complex than everyday
> wheels, but they ARE free to move (with quite low friction) in directions
> other than the driving direction. See:
>
> http://carol.wins.uva.nl/~leo/lego/killough.html
>
> for the basic description and the following mpg movies to see the Killough
> platform in motion:
>
> 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
>
> Zoz
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5655 Wed, 4 Aug 1999 12:25:30 +0800 [alt-beam] test "BEAM" "Zulu35"
testing testing
The Difference between interest and committment
is that when you are interested in something, you
do it only when its convenient. When you are
committed to something, you accept only results,
no excuses ----- Kenneth Blanchard -----
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