Subject:
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Re: The power of Mindstorms
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 5 Mar 1999 13:05:29 GMT
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Viewed:
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1131 times
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Thanks to Peter and Jim for your references,
I am sorry to see that my first posting was not accurate. We have studied these
excellent pages on how to reinforce Lego structures at an earlier point (and
the interesting Math behind it!).
However, our problem is not so much designing the platform and test bed - but
how to make the motors lift the platform.
Until now we have mostly worked with pulleys lifting buckets with weights. But
we have failed coming up with a design for a reliable pulley system involving
five motors pulling each 8 kg+. Especially the placement of the pulleys and
actual wirering is very difficult given the size of the object (a person).
A gear system seems a better bet - especially because we do not have any
ambitions of raising the platform more than just a few cm. Alas, here we find
it difficult to construct a vertical gear lift that can "carry" the platform
without stalling/disintegrating under the stress of deformation and friction.
We continue experimenting with worms gears this week-end.
Anyway; super stable extra high turbo torque solutions/ideas are very welcome -
we would hate to find ourselves wrecked on top of the RCX and five Lego motors!
Thanks again,
Franz-Michael S. Mellbin
--------------------
Jim Thomas wrote:
lego-robotics@crynwr.com (Jim Thomas) writes:
> > Does anyone have a url or a copy they could post?
> > --
> > Regards - Peter Hesketh, Mynyddbach, Mon.
>
>
> Here is the thread which includes both the table and the URL to a very good
> site on this information.
>
> JT
>
> -----Original Message-----
> From: lugnet.robotics@lugnet.com [mailto:lugnet.robotics@lugnet.com]
> Sent: Wednesday, November 11, 1998 11:52 PM
> To: lego-robotics@crynwr.com
> Subject: Re: some interesting lego building
>
>
> This kind of info is on LEGO ON MY MIND too:
> http://www.svc.fcj.hvu.nl/brok/legomind/insights
> Select Triangles in menu
>
> There you'll see some explanatory pictures/animations as well.
>
> Eric Brok
>
>
> Greg Alt wrote in message <199811112132.NAA27218@eskimo.com>...
> > After reading the robot builder's guide on:
> > http://fredm.www.media.mit.edu/people/fredm/projects/6270/
> >
> > I had an idea... There's a really cool section about building strong
> > structures with lego technics pieces, and they list the different
> > possibilities for vertical braces that fit perfectly. The basic idea
> > is that a lego unit is 8 mm wide and 9.6 mm high. Using that, you can
> > solve for integer solutions for vertical braces.
> >
> > So, I got to thinking... perfect diagonal braces should be possible.
> > All you do is solve for integer solutions to the following:
> > x = number of horizontal lego units
> > y = 3 * number of vertical lego units (because you can use 1/3 pieces)
> > r = number of horizontaal units for the diagonal brace
> >
> > (8x)^2 + (9.6/3 * y)^2 = (8r)^2
> > x^2 + (4/25)y^2 = r^2
> >
> > The reasonable length integer solutions are:
> > y x r
> > 10 3 5
> > 15 8 10
> > 20 6 10
> > 30 5 13
> > 40 12 20
> >
> >
> >
> > The y values need to be divided by 3 to get lego units.
> > (e.g. 3.33, 5, 6.66, 10, 13.33) Extra 1/3's just mean that you need
> > an extra 1/3 thick piece vertically.
> >
> >
> > Thought this might be of some interest, as I've found that it is very
> > easy to build something that gets ripped apart by a motor's torque or
> > a bump into a wall.
> >
> > Greg
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Message is in Reply To:
 | | RE: The power of Mindstorms
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| (...) Here is the thread which includes both the table and the URL to a very good site on this information. JT -----Original Message----- From: lugnet.robotics@lugnet.com [mailto:lugnet.robot...ugnet.com] Sent: Wednesday, November 11, 1998 11:52 PM (...) (26 years ago, 4-Mar-99, to lugnet.robotics)
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