 | | Positioning —Carsten Müller
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| | | Hello, I think about a little robot, which is able to move around a 'normal' room/flat and always knows where he stands. The current version of my robot is able to detect the speed and direction he is moving. But as everybody can imagine, the error (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | Re: Positioning —Ian Warfield
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| | | | | (...) I haven't done anything with triangulation - from what I understand, it's hard to implement, not that I could claim any experience with it. But I think you could have a solution similar to the rectangular shapes on the floor: Use tape to make (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | Re: Positioning —David Leeper
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| | | | Hi Carsten, The other day I was trying to get to Target. I didn't know where the store was, so I asked directions. I was told: <i>Go down the street to the second light and make a left, go two more lights and its on the right.</i> Strange. There was (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | | Re: Positioning —Pete Hardie
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| | | | | (...) OTOH, how many mid-course corrections did you make as you walked down the (linear, visible) street to maintain the precise orientation when you reached the light? Landmarks work if they are universally visible, but not if they are beyond the (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | | | Re: Positioning —David Leeper
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| | | | | | Hi Pete, Well, here's what I had in mind. I think it can find landmarks beyond the visible horizon. First, instructions are stored in the map. =-= BEGIN INSTRUCTIONS =-= Go until you see a red brick Turn left Go until you see a green brick Rurn (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | | | | Re: Positioning —Pete Hardie
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| | | | | | (...) My point is more basic - you can find those traffic lights because you are using additional info - that they are all located along the 'grid' of roads, and that if you veer left, you correct when you reach the edge of the pavement (or gravel, (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | | | | RE: Positioning —Ralph Hempel
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| | | | | | | (...) And all we get is the footage from the little CCD camera it was carrying.... Cheers, Ralph Hempel - P.Eng ---...--- Check out pbFORTH for LEGO Mindstorms at: (URL) ---...--- Reply to: rhempel at bmts dot com ---...--- (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | | | | Re: Positioning —David Leeper
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| | | | | | Hi Pete, Those are good points. But I believe they apply to other types of mapping as well. For example, when testing SoftBricks I built a robot that travels a map and if it gets to the desired destination, sends the map to another robot with the (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | | | | Re: Positioning —Pete Hardie
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| | | | | | (...) Some questions I have - what are you using for 'landmark'? How far away can the legobot detect a landmark? When giving directions including a landmark, what are the steps leading up to "...when you get to the X..."? And how does a bot (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | | | | Re: Positioning —David Leeper
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| | | | | | | Hi Pete, The direct answer to what I've used for landmarks is colored marks, like those found on the RCX test pad. If the robot is a few inches to the left or right of the exact path, it'll still find the mark, assuming it's a few inches wide. But (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | | | | Re: Positioning —David Leeper
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| | | | | | | 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 (...) (25 years ago, 27-Jan-00, to lugnet.robotics)
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| | | | | | | | | Re: Positioning —Pete Hardie
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| | | | | | | | (...) 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 (...) (25 years ago, 27-Jan-00, to lugnet.robotics)
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| | | | | | | | | | Re: Positioning —David Leeper
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| | | | | | | | 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 (...) (25 years ago, 28-Jan-00, to lugnet.robotics)
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| | | | | | | | | | Re: Positioning —Mauro Vianna
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| | | | | | | | 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 (...) (25 years ago, 29-Jan-00, to lugnet.robotics)
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| | | | | | | | | | Re: Positioning —David Leeper
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| | | | | | | | 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 (...) (25 years ago, 29-Jan-00, to lugnet.robotics)
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| | | | | | | | | | Re: Positioning —Andy Gombos
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| | | | | | | | | 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 (...) (25 years ago, 30-Jan-00, to lugnet.robotics)
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| | | | | | | | | | | Re: Positioning —Roger Hamlett
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| | | | | | | | | | 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 (...) (25 years ago, 30-Jan-00, to lugnet.robotics)
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| | | | | | | | | | | | Re: Positioning —David Leeper
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| | | | | | | | | | 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 (...) (25 years ago, 31-Jan-00, to lugnet.robotics)
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| | | | | | | | | | | | Re: Positioning —Roger Hamlett
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| | | | | | | | | | (...) 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 (...) (25 years ago, 31-Jan-00, to lugnet.robotics)
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| | | | | | | | | | Re: Positioning —Mauro Vianna
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| | | | | | | | 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 (...) (25 years ago, 30-Jan-00, to lugnet.robotics)
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| | | | | | | | | | Re: Positioning —David Leeper
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| | | | | | | | 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 (...) (25 years ago, 31-Jan-00, to lugnet.robotics)
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| | | | | | | | Re: Positioning —Marco C.
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| | | | | | | (...) come (...) That's one of the reasons why a programmer goes to all the trouble (and fun?) of building a physical model of a bot instead of dealing with over-acurate 3D CG simulations. Ok, now for the Positioning system debate. Just one word: (...) (25 years ago, 27-Jan-00, to lugnet.robotics)
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| | | | | | | | | Re: Positioning —David Leeper
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| | | | | | | | | Hi Marco, Building the robot is definitly fun. But I was really suprised when I built two robots from the same design, ran the same "GO" program in them and they moved differently! 8^o I'm glad to find another ant lover here! I try to check all my (...) (25 years ago, 27-Jan-00, to lugnet.robotics)
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| | | | | | | | | Re: Positioning —Ian Warfield
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| | | | | | | | (...) Ooh ooh - idea! (Piggybacked, of course.) Somebody make an ant robot with a black paintbrush (1) on its back. Wherever the robot goes, it paints a line behind it that it can follow later. Anyone designing a control system could save a lot of (...) (25 years ago, 27-Jan-00, to lugnet.robotics)
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| | | | | | | | | | Re: Positioning (sort of off-topic) —Mike Clemens
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| | | | | | | | In lugnet.robotics, Ian Warfield writes: [...] (...) My 2am-brain free-associated this with the (classic?) "Langston's Ant" simulation. See: (URL) behavior is Very Cool Indeed. - Mike (25 years ago, 28-Jan-00, to lugnet.robotics)
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| | | | | | | | Re: Positioning —Marco C.
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| | | | | | (...) realtime, (...) Nothing I hadn't thought of myself, after sending that msg :D er... is there any human-eye-invisible IR-Ink ? :> ...so I sould have my flood painted with an invisible grid, all over the place, without the knowledge of my wife (...) (25 years ago, 28-Jan-00, to lugnet.robotics)
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| | | | | | Re: Positioning —Steven Vore
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| | | | (...) that's one way. the other is to interalize a map and visualize your reference to it. there was just a (short) article in Backpacker mag (the one with "Europe" on the cover) on this. -- -Steven "Nothin' But Net!" (URL) (25 years ago, 26-Jan-00, to lugnet.robotics)
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| | | | | | Re: Positioning —David Leeper
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| | | | Hi Steven, Yes, and that way works very well, provided you have the storage space for the environmental map and your relative map, and the environment doesn't change from what's stored in the map. The storage space limitation can be reduced by (...) (25 years ago, 26-Jan-00, to lugnet.robotics)
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