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 Robotics / 6840
6839  |  6841
Subject: 
Re: New Lego challenge !
Newsgroups: 
lugnet.robotics
Date: 
Mon, 13 Sep 1999 20:20:51 GMT
Viewed: 
2627 times
  
In lugnet.robotics, Wes Matchett writes:
> 
> Laurentino Martins wrote:
> > 
> > At 03:35 13-09-1999 Monday , Mike Poindexter wrote:
> > > Got it figured out.  Using the principles of right handed recursion, you • can
> > > have the robot follow the right wall and it will eventually get to the • light
> > > and also get out of the maze again.
> > > 
> > > Incidentally, right handed recursion will get you out of any labyrinth
> > > provided that you are not starting inside it already.  If you are already • in
> > > it, it will likely work there as well.  This would then allow the robot to
> > > work in almost any maze you create.
> > 
> > Yes, unfortunately the current firmware implementation from LEGO doesn't
> > have a call stack, so you can not build recursive routines. :-(
> > 
> > On the other hand I can imagine labyrinths where that bot would never be • able to do anything out of them.
> 
> A call stack is not an absolute requirement to do recursive processing, it
> just
> makes it easier.  I have written recursive processes with only an array.
> 
> -Wes

Unfortunately, the default RCX firmware doesn't support arrays, either.

Also, the assertion that you can simply follow a wall in order to traverse an
entire labyrinth actually depends on the maze conforming to a certain
topology.  I'm sure there's probably some technical/mathematical term for it,
but basically, you are assuming that there are no open loops through the
maze.  It is actually very easy to design a maze which will foil a simple wall-
following algorithm.

I don't see any mention of the maze topology in the contest rules.  Perhaps
this would be worthy of clarification?



Message has 1 Reply:
  RE: New Lego challenge !
 
This is a REALLY good idea. Here's something I had kicking around in my head... 1. Making a maze that we can all use is kinda hard. 2. Making a bot small enough to fit a standard buildable maze is really hard. I propose we invert the problem a (...) (27 years ago, 13-Sep-99, to lugnet.robotics)

Message is in Reply To:
  Re: New Lego challenge !
 
(...) A call stack is not an absolute requirement to do recursive processing, it just makes it easier. I have written recursive processes with only an array. -Wes (27 years ago, 13-Sep-99, to lugnet.robotics)

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