Subject:
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Re: LegoX Technic Motor (43362) internals
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Newsgroups:
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lugnet.robotics
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Date:
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Sun, 15 Dec 2002 16:36:42 GMT
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Original-From:
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Steve Baker <SJBAKER1@AIRMAILnospam.NET>
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Viewed:
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6191 times
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Tobbe Arnesson wrote:
> I conducted a quick test with one 71427-002 and one 43362 (with new internals),
> put them back to back with a 8462 wheel on each axel and a 9V small battery box
> being pused in front of them. A _very_ simpel dif. vehicle. As suspected the
> vehicle wont drive in a straight line and it's the new motor that lags behind
> causing the vehicle to turn. It's not a very tight turn though. The path
> describes an arc, like a ')' being 6.7 meters "high" and 1 m wide. Don't know
> the math to turn this into a turning radius.
It's 6.11125 meters.
> Perhaps I should have used gearing
> to make the difference between the two motors more visible.
Yes - it's hard to tell because the difference in speeds will depend on
the load on the motors - loading them either more or less would alter
their characteristics relative to each other.
> It feels like this is not a big difference though, I bet two of the old motors
> would have done about the same arc...
Yes - I think so. Really, every robot that's required to drive more or
less straight needs software to measure it's course and correct for small
motor differences.
Between the dozen or so (supposedly identical) Lego motors I own (all of
the older kind), I see an 11% speed difference between the fastest and the
slowest (with no load other than a rotation sensor).
http://www.sjbaker.org/steve/lego/motor_speed.html
If you had told us the distance between the wheels of your test robot,
we could come up with an estimate of the speed difference between them
and see just how unreasonable this is.
Personally, I'd call Lego an explain that your motors are not the
same and that this makes your robots misbehave - and I'd bet good
money that they'll come through and offer to replace one or both
---------------------------- Steve Baker -------------------------
HomeEmail: <sjbaker1@airmail.net> WorkEmail: <sjbaker@link.com>
HomePage : http://web2.airmail.net/sjbaker1
Projects : http://plib.sf.net http://tuxaqfh.sf.net
http://tuxkart.sf.net http://prettypoly.sf.net
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Message is in Reply To:
 | | Re: Lego® Technic Motor (43362) internals
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| (...) Ah! (...) My friend wont bother much since the boxes are for education at hiw workplace. I conducted a quick test with one 71427-002 and one 43362 (with new internals), put them back to back with a 8462 wheel on each axel and a 9V small (...) (21 years ago, 15-Dec-02, to lugnet.robotics, lugnet.technic)
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