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 Robotics / 10326
  Re: Positioning
 
Hi Pete, I was looking back over you post and realized I didn't answer a couple of your questions. (...) In the program I wrote there are only a few commands. Go forward. Turn left at landmark X. Turn right at landmark X. (...) To be honest, I (...) (24 years ago, 27-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
(...) The main problem I'm seeing is that the legobot has very short sight, and so it can only travel a certain distance before it is nearly sure to miss a landmark, and then be lost. Also, in the Real World (tm), creatures with the limited senses (...) (24 years ago, 27-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
Hi Pete, I agree that the short sight is a problem. In my tests, I used wide strips. Three times as wide as the RCX. And they were no more than a foot apart. So missing them would have been difficult. In real life, you could use similar tricks. For (...) (24 years ago, 28-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
I have been watching this discussion with great interest. I was looking for a solution for this problem since I wanted to program a robot to find his way inside my apartment. The problem I found in the landmark system was that you don't have a (...) (24 years ago, 29-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
Hi Mauro, Maybe I'm misunderstanding, but it seems to me that if you can't tell your robot how to turn correctly, no mapping system would work. The system I used contained a simple TURN LEFT, TURN RIGHT method. Each turn is 45 degrees. I didn't (...) (24 years ago, 29-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
Well, it seems that you all want this to be flexible. How I understand it is that you will have to do at least some preperation to use this landmark system. Now I was thinking about Marco's idea-put a grid of IR beams on the floor, and use the (...) (24 years ago, 30-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
Well, I can tell the robot to turn 45 degrees using timing but it's not precise enough. It would be something about 43-47 degrees. I could use a rotation sensor (but I don't have one) to increase accuracy but there will always be a smal error. After (...) (24 years ago, 30-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
In lugnet.robotics, Andy Gombos <gombos@ne.infi.net> writes: How about a completely different approach?. Two 'beacons'. Each radiates a pulse of IR, and simultaneously, a pulse of ultrasonic tone. With each beacon firing alternately. The receiver (...) (24 years ago, 30-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
Hi Mauro, I understand now, and you're right, it is a concern. I think the way to deal with it is to make landmarks big and hard to miss. This is the way landmarks work in real like. They are big. In this case, I'd say this means using a wide strip (...) (24 years ago, 31-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
Hi Roger, This sounds interesting. Unfortunately, I don't have any experience with Beacon mapping, though I hope to explore it some time in the future. Perhaps someone else on this list has experience in this area? David Leeper (would love to find (...) (24 years ago, 31-Jan-00, to lugnet.robotics)
 
  Re: Positioning
 
(...) The real problem, would be how to return the data to the RCX. The sensor would either have to return the two 'distance' values, and use two sensor inputs, or do the arithmetic itself, and return an X/Y co-ordinate pair on two inputs. Either (...) (24 years ago, 31-Jan-00, to lugnet.robotics)

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