Subject:
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Re: Inverting the robot position problem...
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 28 Apr 1999 19:59:16 GMT
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Original-From:
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Luis Villa <(liv@duke.edu)NoSpam()>
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Viewed:
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3281 times
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On Wed, 28 Apr 1999, Ralph Hempel wrote:
> > The basic idea is similar to the old optical mouse pads -- draw
> > horizontal and vertical lines on the playing field. Use different colors
> > for the horizontal and vertical lines (easily distinguishable by the
> > light sensor's greyscale values). You can then compute relative position
> > changes and from that direction of travel. Obviously, the resolution you can
> > achieve is limited to the spacing of the lines and the accuracy of
> > measuring your bot's motion in between them, but it should be sufficient.
> > The difficulties come from distinguishing the lighter-colored line from the
> > fringe of the darker line, and the varying line widths depending on the
> > angle of travel relative to the line. For instance, travelling parallel
> > to one of the axes will result in no line crossings for that axis (or
> > continuously being on an axis).
>
> This brings out a VERY interesting application. Most bots have trouble
> navigating a real maze because of obvious slippage problems and generally poor
> resolution of sensors. What about inverting the problem and printing (using
> your favorite printer) a map using grids and lines on paper and using the
> light sensor in a plotter bed.
You are right about the limitations of image based maze followers, but
with you don't even need to get that complicated- any bot that can follow
a wall using touch sensors can do a maze reasonably well. Picture a blind
man walking along a wall, and when he feels the wall end, he turns until
he figures out what his options are at the intersection. We have a couple
in the lab doing it, and hopefully I'll coax an RCX to do it soon.
OTOH, the two color grid has a lot of other applications- does anyone
have any ideas on how to make one? I'm thinking of using thin
pin-striping tape from a hobby shop, but I'm open to other suggestions...
My two cents-
Luis
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--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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Message has 1 Reply:
 | | Re: Inverting the robot position problem...
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| (...) That was what I had intended to use -- 1/8" tape spaced at 1" centers on a white background. I was thinking black and red should be sufficiently distinguishable from each other, but that will probably take experimentation. John A. Tamplin (...) (27 years ago, 28-Apr-99, to lugnet.robotics)
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Message is in Reply To:
| | Inverting the robot position problem...
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| (...) This brings out a VERY interesting application. Most bots have trouble navigating a real maze because of obvious slippage problems and generally poor resolution of sensors. What about inverting the problem and printing (using your favorite (...) (27 years ago, 28-Apr-99, to lugnet.robotics)
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