OK.. I'll play a little bit (Mom said I could) 8).

I think most navigation problems are broken down to their various parts and
then conquered one at a time.  In this case, Annie describes what is
essentially an infinitely variable environment - if I interpret the rules
correctly.

If I'm right then just about anything could be in front of the robot - and
there is always a 50% chance of finding a successful bridge but not assured
discovery of a successful path on that bridge.  Could we come up with a
basic set of hierarchical responses to the environment and then model the
robot behavior accordingly?

Say:

1. preserve life (robot life)
2. explore
3. record and leave a record for others to follow (if I understood the rules
correctly).
4. cross the bridge (successfully)
5. procreate with other robots
6. become sentient
7. make the humans cross the damn bridge


Ok... ignore the last three.

Dan

-----Original Message-----
From: Anne Ogborn <anniepoo@NETMAGIC.NET>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: Thursday, August 26, 1999 8:50 PM
Subject: Re: [OT] a robotengedanken experiment


>> Now it gets harder :-)
>> Depends on how many trials you are allowed.
>> If number of trials is staistically small and tiles are cunningly
designed
>> to fool an only moderately smart robot then option 1 to 3 may well be
>> better (Use the Force, Annie).
>
>No, I think I implied that the # of trials is statistically large. And
presumably
>the right/left position of the crossable tile is random.
>
>> eg 2 tiles, one with a clear optical path but uncrossable, the other with
a
>> zigzag path so no line of sight but crossable, would lead a "I can see
>> across  - it must be OK"decision maker to die every time.
>
>>
>> Assuming the uncrossable tile does not give itself away and allow you to
>> leave after entry - ie you must commit to one or other and then enter,
then
>> one could design various sensors to sense probable problems.
>
>no reason to think it would be so designed.  I was thinking of tiles with
>more likely 'real world' situations - like, for example, a tile with a
number
>of office chairs sitting on it, or a tile with a number of those wire mesh
>trash cans, or one littered with clothes.
>
>> IF the tile
>> designer is TRYING to trap you then he will win as he (she probably in
this
>> case ;-)) has a brain and the robot is only programmed using a brain.
>
>that's not the objective, and of course making an uncrossable tile is as
>simple as making the tile be "nothing" - the robot physically can't cross.
>I'm not seriously suggesting we do this as a contest,
>I'm suggesting thinking about it might lead to understanding some piece of
>robot navigation.
>
>>
>> THUNKS
>>
>> I reckon option 3 is liable to be pretty good :-)
>>
>> I may have missed what you were driving at. Maybe a bit more description
>> would be useful.
>
>
>> Various assumptions need also to be laid out eg
>> - Can you only test before entry to tile.
>
>no. You can do anything physically possible except change the robot's
locomotion
>or add a human driver. Indeed, I'd be very suprised if the robot's
algorithm wasn't
>something along the lines of wall following. examine patches in front of
you. If you
>think they're not safely passable, consider them walls and use a wall
following algorithm.
>
>> - May you "save" yourself by leving an uncrossable tile if you detect it.
>
>sure.
>
>> - Can extra sensors be mounted?
>
>yes.  I said that in the original post.
>
>The physical setup seems pretty straightforward.
>Here's a little robot, it needs to navigate from A to B, and in between is
>known to be a path.  That's the navigation problem.
>What I've done is reduce it to the problem of not getting stuck. Since
there's no
>requirement for speed getting to the goal, even an algorithm of moving
randomly into
>'safe' areas will work.