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Subject: 
Re: Autonomous Robot
Newsgroups: 
lugnet.robotics
Date: 
Wed, 9 Aug 2000 22:07:52 GMT
Original-From: 
John Barnes <BARNES@SENSORS.COMnomorespam>
Viewed: 
478 times
  
I think that this autonomous robot thread has been the most interesting
one on lugnet for a while.

I am fascinated by all the creativity which pours out in response to this most
interesting challenge.

Personally, I have cheated this issue by using ultrasonics, but that isn't
to say
I'm not interested in the problem as laid out.

I have a suggestion, which I think may date back 50 years to the early days of
radio direction finding. I believe the British Isles are (were) surrounded
by a system
of transmitters with counter-rotating antennas, one rpm. Each had a different
signal, so you listened and counted the time for each signal and deduced your
resulting bearing from the transmitter.

Can't you do this with two counter-rotating lasers! The RCX sits out there and
counts out the time between three hits, 1 - 2 - 1 for example. The relative
time
gives the angle. There is an ambiguity but if the transmitter is in the
corner of the
room, then the ambigous position is not real.

A crude approach at range, is then to move at right angles to the beam some
known
small distance using odometry which should be good for a short straight
line and then
resample the transmitter's new angle. You now have all the info to solve
for the range.

I have no idea if it can be made to work, I haven't tried it.

Also, I wonder if you need lasers or if a pair of counter-rotating
mini-maglites whould do it!
They'd be a lot cheaper for testing out the idea.

JB



Message has 2 Replies:
  Re: Autonomous Robot
 
in article 4.2.0.58.20000809145...ailserver, John Barnes at lego-robotics@crynwr.com wrote on 8/9/00 3:07 PM: (...) I'm enjoying it too. I hope my employer isn't reading this group! :) If so, Hi John, I'll have that server done right away, working (...) (24 years ago, 9-Aug-00, to lugnet.robotics)
  Re: Autonomous Robot
 
(...) Fun isn't it! (...) Wait, wait, wait. You must need more than two numbers. Mathematically, you can't specify a 2D position without TWO numbers (eg X and Y, or Heading and Range, or two angles). Your timing between three hits from two (...) (24 years ago, 10-Aug-00, to lugnet.robotics)

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