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Thread: GPS type technology for machine slide position ?

  1. #1
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    Default GPS type technology for machine slide position ?

    Could GPS BE scaled down for machine tools. Drone positioning systems are talking about centimeter accuracy.The sender and the receiver seem to have precision atomic clocks and calculate the time it takes for a radio signal to travel between them.Of course the system wouldn't actually use the gps satelitesI see these kids with some kind of hand held device playing an imaginary game of tennis on a giant tv screen.I think this uses this system Does anyone have any thoughts on this..Edwin Dirnbeck

  2. #2
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    Short answer: No
    Work hard play hard

  3. #3
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    Long answer: Why bother.
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

  4. #4
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    Unmanned warehouse logistics use a beacon system which might interest you, but unlikely to be useful for machining.


    for example https://youtu.be/mEzCMS50mtE
    "...do you not think you have enough machines?"

  5. #5
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    GPS in the shop is best suited for finding your lost tools!

    Though RFID would be better.

  6. #6
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    It would be rather useless to use a location to a centimeter for milling. If you found an application for it, Making 3 transmitters with clocks that hold that level of accuracy may require temperature control to keep the oscillators stable.

    I have some experience with tape backup systems which have a library of tapes arranged in rows and columns that a robotic arm picks from. All of the libraries used a similar system of dead reckoning to get to the right row / column area and then use optical or mechanical sensors to align the "hand" before trying to grab the tape.
    Measure twice. Cut once. Weld. Repeat.
    ( Welding solves many problems.)

  7. #7
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    The distance to the satellite from the calculated location on the ground is enormous compared to the required accuracy. The ratio of the distance from any practical transmitters to the location of a machine tool would tiny. If a signal takes a second to reach the receiver you can slice that up quite a bit. If we're talking nanoseconds to begin with, there's not a lot further you can (economically, practically) slice or compare them to derive a measurement.
    "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

  8. #8
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    I think Edwin was suggesting GPS like technology and said it would NOT use GPS satellites. GPS technology is based on trilateration and indeed there work in this area - trilateration of machine tools using 3 interferometers which measure accurately to a millionth of an inch (how gauge blocks are calibrated). I have not read the papers on it or seen a commercial application, but its not so far out there an idea that no one's thinking about it. I've had the pleasure of getting to play with an interferometer and its quite neat stuff. You can accurately tell someones weight by measuring the deflection of the concrete slab they're standing on
    Last edited by Mcgyver; 10-08-2018 at 04:48 PM.
    .

  9. #9
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    Short answer: yes.

    Long answer:There are existing systems that use multiple antennas and measure carrier wave phase difference between arriving signals to determine roll, pitch, heading and offset.

    But since these systems are like $15k, it is cheaper just to use a $150 glass scale.

    Plus, the offset measurements don't provide accuracy at the tenths level.

    So... No.

  10. #10
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    Too many variables to allow for consistent accuracy. Look how trees, walls and roofs interfere with GPS.

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