Subject:
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Re: 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 20:07:55 GMT
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Original-From:
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L. M. Lloyd <lee@advfilms.comANTISPAM>
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Viewed:
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576 times
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Nancy Evelyn Gold wrote:
> 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).
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:
http://www.kl.net/scans/8000/8880/
These instructions have a lot of really neat and efficient ways to do
things. Unfortunately some of the neatest things they did in that kit
require parts that, to my knowledge, only come with the 8880, but it is
still great for ideas, and a lot of the special parts could probably be
worked around.
> 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.
The one I am working on (with the help of those special Super Car parts:-)
is 4 wheel drive and 4 wheel steering. This model needs a total of 6
U-joints, one at each corner and 2 to connect up to the motors.
> 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.
Please let us know when you get this up! I, for one, can't wait to see what
other people are doing in this area.
> 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 have been debating whether to use an angle sensor, or fiber optics and
the light sensor to track my steering. I would love to hear what other
methods people are using.
> 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.
Interesting, I had not thought of using pneumatics this way.
--
__________________
L. M. Lloyd
lee@advfilms.com
SGI Animator
ADV Films USA
__________________
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Message has 1 Reply:
 | | Re: 4x4 'bots (was Re: Misc. Lego parts)
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| (...) I just thought of an idea for making a servo for steering... I'm not 100% sure this will work, as I don't have an angle sensor, but here you go: You'll need a fixed width font: | <--- drive axel +-------+ |o o o o| <--- 1x4 technic beam (...) (26 years ago, 22-Nov-98, to lugnet.robotics)
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Message is in Reply To:
| | 4x4 'bots (was Re: Misc. Lego parts)
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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 (...) (26 years ago, 21-Nov-98, to lugnet.robotics)
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