Subject:
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Re: moving in a straight line with two motors?
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Newsgroups:
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lugnet.robotics
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Date:
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Sat, 14 Nov 1998 22:38:36 GMT
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Original-From:
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Jason S. Mantor <jason@inphotek.IHATESPAMcom>
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Viewed:
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4969 times
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so do you still have a big track ? Mine is unfortunately missing a wheel : (
Jason@Inphotek.com
Giesen, Oliver <lego-robotics@crynwr.com> wrote in article <E10BAC791F2ED2119D920008C7B128C8013CB5@tornt6.mdshealth.com>...
> G'Day
> My 3 cents (Canadian, Eh).
> The most elegant solution I have seen to this problem I believe came from an
> old Milton Bradly 'Big Trak', in which the designers used a magnetic clutch.
> The idea is simple , getting the forces involved to balance may be more
> tricky I have not yet tried this with Lego(TM) bricks.
>
> Basically you get two large pulleys (or bars) and mount two magnets opposite
> each other on the same side, one pulley has the two north poles facing out
> and one has the two south poles facing out, when the two pulleys are mounted
> so that the magnets face each other the two pairs of magnates will attract
> each other and then when one axle is turned the other will turn with it.
>
> Now the tricky(?) part... the idea is that when both wheels are driving
> forward together the difference in torque will be low enough and the magnets
> strong enough that the two axles will stay in step. When turning by only
> driving one motor and thus only side of our little clutch the torque will be
> great enough to unstick the magnets and one side will spin freely.
>
> Its kind of cool to watch.
>
> This also seems to work better if the clutch turns faster that the wheels
> being driven, so it should be placed closer to the motor than the drive
> wheel end of the transmission drive chain.
>
> I hope I have been clear in my description, it is obvious when you see
> it.(sorry no web page yet)(;(
>
> Cheers!
> Oliver.
> ogiesen@mdsintl.com
> sent to lego-robotics@crynwr.com
>
> Horrible ASCII art:
> Top View
>
> | < axle
> | <
> ---------- < pulley 1
> n n < two magnets mounted on pulley 1's surface
> < air space
> s s < two magnets mounted on pulley
> ---------- < pulley 2
> | <
> | < other axle
>
> -----Original Message-----
> From: lugnet.robotics@lugnet.com [mailto:lugnet.robotics@lugnet.com]
> Sent: Thursday, November 12, 1998 10:11 PM
> To: lego-robotics@crynwr.com
> Subject: moving in a straight line with two motors?
>
>
> Hi,
>
> One of the first things I ran into when making a mobile 'bot using one
> motor for each of two drive wheels was the mismatch in their speed.
> Needless to say, it's a nice way to make curved path. Not what I want.
>
> <snip>
>
> Unfortunately, gear slop keeps this from working well for me. Any
> suggestions?
>
> Thanks,
> -Tim
>
> --
> Tim and/or Shelley Rueger - rueger "at" io.com
> WWW page: http://www.io.com/~rueger/
>
>
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