Need Help with a stitch regulator

Discussion in 'The Projects Forum' started by Brian2007, Dec 14, 2007.

  1. Brian2007

    Thread Starter New Member

    Dec 14, 2007
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    0
    I need help with a stitch regulator: The machine head can move in both the x and y axis at the same time and needs to control bothe the speed of the motor and the number of turns. The number of revolutions per/in of travel needs to be adjustable. Also the the speed of the motor needs to vary with the speed of travel. Current applications of this use encoders on the x and y axis and a DC servo for power. The machine movement is by hand and the the power is for the machine head. Anyone have any ideas?

    Thanks
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    282
    I get the motor speed varying with the manual advance to keep the stitch interval the same, but the number of turns is a bit hard to understand.

    In the old days, a couple of servo amps would have run the machine head. The variable stitch length - if I understand the adjustable revs per inch properly - makes it harder. It might be easier approaching this with a microprocessor reading the X & Y encoders and controlling the motor speed through PWM.

    Are you able to do the electronics and programming this will entail?
     
  3. Brian2007

    Thread Starter New Member

    Dec 14, 2007
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    Ok so I didn't explain it correctly, the machine makes 1 stitch per revolution. It need to be adjustable from about 8 to 16 stitches per/in.
     
  4. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    So the motor needs to speed up for more stitches and slow down for less stitches? I take it the X/Y is fixed?
     
  5. Brian2007

    Thread Starter New Member

    Dec 14, 2007
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    OK as the machine is moved manually the speed will not be a constant, travel may be in both axis at the same time, as when making a circle, so there is input from both the x and y encoder, Yes the motor will need to vary speed to keep the stitch count the same as speed and direction of travel changes.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Do you have particular motors in mind/on hand?

    If you're going with DC motors, you might consider an L298 dual full-bridge driver IC.

    For rotary encoders, you might consider Hall-effect devices.

    Stepper motors might be worth considering, but would have to be fairly large or geared down to provide the torque necessary (read:slow)
     
  7. Brian2007

    Thread Starter New Member

    Dec 14, 2007
    4
    0
    This device has been and is currently being built. but you know how it is I want to try it myself. Currently the best of these regulators are driving servo motors, these are small units as not a lot of power is required. I do have some pdf manuals on whats already out there.
     
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