Subject:
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Re: localization (was re: GPS)
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 11 Jan 2006 18:14:09 GMT
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Original-From:
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Chris 'Xenon' Hanson <xenon@3dnature(AntiSpam).com>
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Viewed:
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1743 times
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I've always been partial to ultrasonic rangefinding. It's not too difficult indoors
under controlled circumstances. The old Nintendo PowerGlove used this technique. For robot
localization, you'd probably want a minimum of three non-moving marker beacons, possibly
four. These beacons give a (mostly) omnidirectional ultrasonic chirp when commanded by the
bot, and the bot times how long before it receives the chirp. With fast enough processing,
some pretty decent accuracy can be achieved.
You need to have each beacon located far enough from the others and in a different
enough direction that triangulation is possible.
It's sort of like GPS, only indoors and sonic instead of radio.
You'd probably need to use a radio broadcast from the bot to the marker to tell it when
to chirp.
It's something that would have to be assembled into a complete tracking system, it
would be nearly impossible for most hobbyists to assemble the hardware and software.
I know John Barnes has done a lot of ultrasonic work, perhaps he could comment on the
practicality of making a system like this available. I imagine due to the
density/complexity of the positioning data, it would need to talk bluetooth or some other
fast high-level protocol to the bot.
This would be a useful system for much more than just Mindstorms, obviously.
The one downside is that, like GPS, it doesn't tell you heading, just position and
direction of travel.
--
Chris 'Xenon' Hanson | Xenon @ 3D Nature | http://www.3DNature.com/
"I set the wheels in motion, turn up all the machines, activate the programs,
and run behind the scenes. I set the clouds in motion, turn up light and sound,
activate the window, and watch the world go 'round." -Prime Mover, Rush.
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Message has 1 Reply:
 | | Re: localization (was re: GPS)
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| (...) I have tried all sorts of tricks with ultrasonic stuff, you're right :) There are a couple of different schemes for the ultrasonic beacon type things. You can have ones which are triggered from the 'bot via radio or IR. I've tried the IR one. (...) (18 years ago, 11-Jan-06, to lugnet.robotics)
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Message is in Reply To:
| | Re: localization (was re: GPS)
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| (...) No, you do in general have to have them looking at the same satellites in the constellation at the same time, and even then there was a good bit of number manipulation to do. But the group I cave with did this with two laptops (to record the (...) (18 years ago, 11-Jan-06, to lugnet.robotics)
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