Subject:
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Re: 0.5 degree resolution with rotation sensor
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 7 Jun 2000 10:22:57 GMT
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Viewed:
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959 times
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In lugnet.robotics, Ricardo Andrade writes:
> I don't really need it to be really precise, because, yes, the gear train is a
> huge factor in a situation like that. I only built the gear train and I'm
> using another rotation sensor as the reference for my controller. Depending on
> the position I put the 2nd wheel, the controller should move the other one to
> the same position. And for that it's working great. I know, I didn't have to
> build the gear train for that, but I just wanted to try and see if it was
> going to work. After all I just started playing with the RCX and now NQC...
>
> And yep, Mauro, I'm brazilian... :o)
I did a design a little while ago, using the ultrasonic rangefinder (this is
John Barnes's original design 'redesigned' by me, and built as a PCB), as a
'rangefinder', with a meter needle. Obviously to get reasonable resolution on
the needle, required an accurate ability to measure angle, so I used the
rotation sensor, with a worm reduction gearbox. The backlash is avoidable, by
the simple expedient (in a lightly loaded device like this), of 'spring
loading' the needle. This approach is common in a lot of mechanical devices,
and similar approaches can also be used with a bit of software 'tweaking'. So
(for instance) on a milling machine, it is normal practice to allways approach
your required location from the same direction (thereby removing the need to
worry about backlash). You can do the same in the RCX software, allways going
past the required location, and moving up to it from the same side. With a
rubber band biasing the slack out of the gearbox, you can get accuracy limited
only (really) by the accuracy of the lego gears!.
Best Wishes
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Message is in Reply To:
 | | Re: 0.5 degree resolution with rotation sensor
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| I don't really need it to be really precise, because, yes, the gear train is a huge factor in a situation like that. I only built the gear train and I'm using another rotation sensor as the reference for my controller. Depending on the position I (...) (24 years ago, 5-Jun-00, to lugnet.robotics)
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