Subject:
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4x4 'bots (was Re: Misc. Lego parts)
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Newsgroups:
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lugnet.robotics
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Date:
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Sat, 21 Nov 1998 10:04:25 GMT
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Original-From:
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Nancy Evelyn Gold <{nancyg@sgi.com}antispam{}>
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Viewed:
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947 times
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Wow! I thought I was the only nut working on such a 'bot.
4x4 models are my fetish. Over the last couple of years I've
built several with just Technic parts.
I've been hacking for two weeks on a non-sprung steering system
with drive shafts. Today I realized that a 8880 would give me the
parts I need for most of my plans (including a transmission).
I'm kicking myself for not buying one last year.
Mark, to answer your question about U-joints, I thing the magic
number is 8 if you want independent front/rear suspension
(two at each corner). The draft shaft doesn't need one unless
you're planning on a live rear axle, then you only need one for
the rear (total 5). You might need three for the front two corners,
I haven't really tried it.
To be really cool you'll also need three differentials.
I built a fixed hub 4x4 that steered by reversing the opposite wheels.
It used four motors and was a blast to watch wander around the office.
The front bumper had two sensors so the 'bot would backup and turn
based on which side of the bumper hit the obstacle. I even wrote
a "futility" detector to deal with corners.
I've got pictures of the 'bot assembled and several of it as I took
it apart. Sometime soon I'll get around to putting them up on one of
my web sites with the nqcc code.
The front half of my latest creation is on a test gig. Steering without
a servo motor is a pain. My kludge mostly works. I'm trying to use
the optical sensor to detect when the wheels are straight.
I'm considering pneumatic steering also. My S@H order should be here
Monday with a bunch of cylinders and a compressor. To get an air tank
I'm going to need to buy a set.
--- Nancy
"L. M. Lloyd" wrote:
>
> I just went through exactly the same thing you are going through. My
> solution was to pick up one of the many Super Cars that regularly go
> on sale or auction on rec.toys.lego
>
> Mark Hoy wrote:
> >
> > Part I think I need/want:
> > -4 Shocks
> > -universal joints, (don't know many I'd need for a 4 wheel drive
> > vehicle with
> > steering and shocks)
> > -1x2 block with two holes
> > -1x1 block with one hole
> >
> > I'd like to build a vehicle with four wheel drive, shocks and
> > steering.
> > The super car seems to have this, but no availability of the kit.
--
Nancy Evelyn Gold (nancyg@sgi.com)
1993 BMW K1100LT "Chloe" - DoD# 1184 - BMWMOA
++ Only Open DVD Delivers! Just say no to DIVX. ++
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Message has 1 Reply:
 | | Re: 4x4 'bots (was Re: Misc. Lego parts)
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| (...) If your working on your own 4x4 designs I wound definitely take a look at the 8880 Super Car instructions you can find them at: (URL) instructions have a lot of really neat and efficient ways to do things. Unfortunately some of the neatest (...) (26 years ago, 21-Nov-98, to lugnet.robotics)
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