Subject:
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Re: Unit LNE of the dinochrome brigade (Was: Rock Crawling)
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Newsgroups:
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lugnet.org.us.laflrc, lugnet.robotics, lugnet.technic
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Date:
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Tue, 23 Jan 2007 03:31:17 GMT
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Reply-To:
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Geoffrey Hyde <gdothyde@bigponddo#NoSpam#tnetdotau>
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Viewed:
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2173 times
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"Brian Davis" <brdavis@iusb.edu> wrote in message
news:JCAvs8.H94@lugnet.com...
> The more I thought about this, the more I liked this idea: I wanted to
> make a
> really high-mobility vehicle, but the problem with wheels is they are
> really
> stopped by steps greater than their own radius (well, partially, ignoring
> pushing from behind). Not to mention that the Really Cool wheels (Power
> Puller)
> are a tad hard to find, so... I thought of PackBot, and with the higher
> torque
> NXT motors, thought I might make a stab at it. The result works pretty
> well:
> handling piles of laundry, crawling over LEGO, climbing 30° wood slopes,
> uprighting itself after flipping, smashing minifigs, etc. The only problem
> is it
> needs just a *little* more length to reliably crawl over my leg, and of
> course
> treads are not the highest friction in the LEGO universe (and, I'm out of
> treads).
Have you considered using the new 5-wide treads found in the new Technic
Snowmobile? They seem a lot more suited to driving over most surfaces with
their added width, and they're relatively new, so perhaps we can find out if
they're really as good as they look.
> The first problem was transmitting the drive motion through the "shoulder"
> joint
> of the flipper arms. Then the second, bigger problem was reinforcing the
> heck
> out of the structure to keep it from tearing itself apart: the first
> version
> could easily torque the whole front off, while this one doesn't even flex.
> And,
> it's all studless*
If you are going to get more photographs, I could use ideas on how to use
the studless elements in constructions. I'm at a relative shortage of
studless model instruction books to take techniques out of so I'd appreciate
a rundown any studless techniques you can explain in failry simple terms.
> Brickshelf folder of static images:
> http://www.brickshelf.com/cgi-bin/gallery.cgi?f=229082
>
> And a few videos. I like the one where it crawls over the old Technic
> Space
> Shuttle...
> LNE vs the Empire: http://www.youtube.com/watch?v=iNXHKtnFBcc
> Studless meets studded: http://www.youtube.com/watch?v=4ik640MLj6k
> On point: http://www.youtube.com/watch?v=WwBYvs7vq_0
Okay, the first was pretty good, the second it seemed to have a few problems
getting over the Space Shuttle itself, and eventually looked like it was
staggering around drunkenly after finally having succeeded, and the final
video was not too bad but a little short, I'd have appreciated a bit of
camera zoom/pan or the model running around showing how well it can turn.
> *OK, there are six studs: I needed someplace to put the crazy minifig
> driver.
> More curiously, I found myself having the same odd issue that I think John
> Brost
> mentioned earlier: it's gotten so natural to build studless for me now,
> that it
> was hard to try to make it a "hybrid". I think I can do a little better,
> actually for a hybrid version.
I wish I could get building studless "natural" myself. I'm intrigued by the
ways you can put it together, and it's a lot more complex than the simple
system implies. Especially when you actually have to think, now, how am I
going to take the power off the NXT and drive it down the side of my model
to somewhere I can use it.
As I said earlier, I'd appreciate any ideas on studless building you can
explain in fairly simple terms.
In fact, I'm hoping someone out there has or is working on a compilation of
studless building techniques.
A comment on your model's driving rpinciples, have you thought about trying
to get the treads themselves to slide as well as turn, so that you can not
only flip them but turn them over to the other side so as to take more
advantage of the fact that one side is slightly raised near one end? It
might make the model a bit bigger, but maybe you can make a mechanism that
accomplishes it with a gear rack that runs off an idler sprocket from the
main drive.
Also, for a wheeled version, have you tried building a ganged pair of front
wheels in a triangular formation? There was a movie that featured a very
large custom-built vehicle where the wheels simply rotated backwards,
flipping slowly backwards around the collective axis if they hit something
they couldn't easily drive over, until they drove over it.
I'd imagine it would be pretty complex to build in LEGO nowadys, but doable.
:)
Cheers ...
Geoffrey Hyde
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