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 Organizations / Canada / rtlToronto / 8764
8763  |  8765
Subject: 
Re: rtlToronto15 January issues
Newsgroups: 
lugnet.org.ca.rtltoronto
Date: 
Mon, 25 Aug 2003 16:52:40 GMT
Viewed: 
463 times
  
In lugnet.org.ca.rtltoronto, Dan Boger wrote:
On Mon, Aug 25, 2003 at 04:22:43PM +0000, Chris Magno wrote:
Wouldn't you have to mark the "correct" way on each joint, and have
different markers for the two sides to follow? One robot would
follow the "red" markings, while the other follows the "blue"?

Dan, at the last dinner (which you missed) :)

Hey, INS was getting possessive, and didn't want to let me leave the
country.  Now that that's fixed, maybe we'll visit for the next event :)

derek pointed out that any marking is pointless cause you don't know
from which angle the robot is reading the mark.

at a simple "T" a read stripe means turn left.... BUT if the robot
reads that red stripe from the "front" or the "back" the same go left
code could send it in either direction.

Maybe I'm dense.  Actually, forget the maybe - but here's what I'm
thinking of (bad ascii art follows):

                   v
   *---<T>---<T>--<T>---*
blue    |     |    |    red
        |     |    |
        |     |    |
        |     |    |
        +----<T>---+
      ^

T - a T joint (duh!)
- a blue marker
< - a red marker

Calum was saying that at each T joint, there would be a marker as to the
"right" way to go to reach the objective.  But, you could go on
alternate routes and still find your way back using markers.

So the blue bot, gets to the first T, and can either follow the blue
marker, or go explore.  Then, when it gets to the second T, it has the
same options - follow the blue marker (which would point it twards a way
to the objective), or go explore.  If it gets to the T marked with a
'v', and chooses to go down, it will reach the next 'T' (marked with a
'^'), and know it needs to reverse directions in order to reach it's
objective.  All the while, the Red robot doesn't care about all these
blue marks, as it's looking for red ones.

Does that make sense?  Should I go sit on the sidelines a little longer?

:)

I like it.  The original thought was that before each joint there would be 1
strip or 2  1 strip means 'go left' (as left as left can be in a 3 d grid), or 2
stripes means go right (again, same).

As pointed out, however, which way's left or right.  I think that, from the
starting position, if we take the ground as down, then the robot would have to
know which way is 'up or down' (one more factor of progamming)... thus if it
came to an intersection and it knows which way is down, then it would also know
which way left and right is for the direction its facing.

THis, of course, falls apart when you put vertical intersections--so the colours
after the junction, as Dan showed, would be a much better solution--your robot
would have to scan past the juncture in order to proceed.

I like it.

Dave K



Message is in Reply To:
  Re: rtlToronto15 January issues
 
(...) Hey, INS was getting possessive, and didn't want to let me leave the country. Now that that's fixed, maybe we'll visit for the next event :) (...) Maybe I'm dense. Actually, forget the maybe - but here's what I'm thinking of (bad ascii art (...) (21 years ago, 25-Aug-03, to lugnet.org.ca.rtltoronto)

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