Subject:
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Re: Positioning
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 26 Jan 2000 21:17:32 GMT
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Viewed:
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817 times
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Hi Pete,
Those are good points. But I believe they apply to other types of mapping as
well. For example, when testing SoftBricks I built a robot that travels a map
and if it gets to the desired destination, sends the map to another robot with
the intent of that robot following the map to join the first robot. It worked
great, except no two robots drive exactly alike and sometimes the second robot
got "lost". And this was with a simple timing map. Although I didn't test it,
my feeling is that a landmark map would work better in that case because they
don't depend on the precision of rotation sensors, or get thrown off by
slipage or different drive trains. Landmark maps are a bit more resistant to
the differences in how robots move. Just a bit.
The real problem seems to me to lie in the "GO" part of following the
map. "GO" isn't a precise thing. Perhaps different types of algorithms could
solve this problem? And there's always the trick of drawing a black line on
the floor, but that always seemed like "cheating" to me.
David Leeper (starts looking for new landmarks when lost, or asks directions)
In lugnet.robotics, Pete Hardie <pete.hardie@dvsg.sciatl.com> writes:
> David Leeper wrote:
> >
> > Hi Pete,
> >
> > Well, here's what I had in mind. I think it can find landmarks beyond the
> > visible horizon.
> >
> > First, instructions are stored in the map.
> >
> > =-= BEGIN INSTRUCTIONS =-=
> > Go until you see a red brick
> > Turn left
> > Go until you see a green brick
> > Rurn right
> > Go until you see a black brick
> > Stop
> > =-= END INSTRUCTIONS =-=
> >
> > Just like I couldn't see all the trafic lights involved on my trip to the
> > store when I first started out, the robot doesn't need to see the red, • green,
> > or black bricks to start travelling. Just start going! The red brick may be • a
> > few inches away, it make be 70 yards away. Just go and look for a red brick.
> > When you see it, turn left.
> >
> > David Leeper (can make a left at the next gas station, even if it's 100 • miles
> > away)
>
> My point is more basic - you can find those traffic lights because you are • using
> additional info - that they are all located along the 'grid' of roads, and • that
> if you veer left, you correct when you reach the edge of the pavement (or
> gravel,
> in some areas...)
>
> The typical legobot, OTOH, is closer to an explorer in the Antarctic - he can
> see
> only 5 feet ahead, and can't quite walk a straight line. Give him a rope • strung
> between landmarks, and he can walk it, or make the landmarks bright lights • that
> he can see through the snow and he can track on it. But without a visible • goal
> and reliable dead reckoning, he gets lost, wandering in a big circle, until
> he finds an abandoned house and ends up in the basement, standing in the
> corner.....
>
>
> --
> Pete Hardie | Goalie, DVSG Dart Team
> Scientific Atlanta |
> Digital Video Services Group |
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Message has 1 Reply:
 | | Re: Positioning
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| (...) Some questions I have - what are you using for 'landmark'? How far away can the legobot detect a landmark? When giving directions including a landmark, what are the steps leading up to "...when you get to the X..."? And how does a bot (...) (24 years ago, 26-Jan-00, to lugnet.robotics)
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Message is in Reply To:
| | Re: Positioning
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| (...) My point is more basic - you can find those traffic lights because you are using additional info - that they are all located along the 'grid' of roads, and that if you veer left, you correct when you reach the edge of the pavement (or gravel, (...) (24 years ago, 26-Jan-00, to lugnet.robotics)
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