Anti-Sway Crane.

Discussion in 'General Electronics Chat' started by t00t, Dec 10, 2015.

  1. t00t

    Thread Starter Member

    Jan 22, 2015
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    Anyone in the lifting industry can advise on anti-sway crane programming ?

    I wanna know if thats the only way to stop the swaying movement of a crane during lifting .

    Have anyone of you guys seen anything besides this anti-sway program to stop the swaying movement of a crane during lifting.

    Reason behind this is because cost is high for such a program.

    I am thinking of making a skeleton structure and somehow tie it to the crane so that my lifting operation become anti sway .

    Would be grateful for any advise .

    Thank You

    crane is as in the picture below .

    crane.jpg
     
    Last edited: Dec 10, 2015
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You could base it on the inverted pendulum principle.
    See Picmicro AN964 for details, also a few Utube videos on the subject.
    For a crane I would imagine you may need Hydraulic (cylinder?) stabilizer each side?
    Max.
     
  3. BR-549

    Well-Known Member

    Sep 22, 2013
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    What part of the crane is swaying?
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You didn't mention it was a overhead gantry crane, Is it the lifting mechanism you want anti sway, or does the gantry itself oscillate?
    Max.
     
  5. t00t

    Thread Starter Member

    Jan 22, 2015
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    From the videos i see on YouTube , How they do it is they have a sensor and the crane catches up during the half swing thus making the lift anti swing.

    I am using the crane in the picture to pick up something that is 1Meter by 1 Meter by 1 Meter .

    When is starts lifting the load , the load starts swaying . I need the anti sway on the load for automation .


    Thank you .
     
  6. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Not a crane driver myself but working for many years in close contact with ships' and shore crane drivers.

    I understand that for sway you allude to the balance acquired by the weight when lifted out of the vertical or the crane displaced sudenly towards a certain point.

    In both types of cranes (gantry or common ones) the trick to kill/cut the balance is to bring quickly the suspension point (where the weight is actually hanging from) obviously near the jib's or boom's end so it comes on the vertical, directly above the weight. Now that I think. of it, you know that. Sorry.
    That effect and the above solution I know is considered in the software of big cranes. I recall they told me it involved angle wrt vertical, weight and length of wires as deployed at the moment.

    Never thought that a bridge crane could suffer the problem, but, why not?

    Curious, what starts the sway in your case? Lifting out of the vertical or too fast traveling?
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It sounds as though they use the same principle as the Pic App.
    But with a crane you would have a possible 360°, but predominately 2 axis swing, do you need correction in the two axis or primarily one?
    Max.
     
  8. t00t

    Thread Starter Member

    Jan 22, 2015
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    The crane has 2 speed . I have tried to move it at the lower speed but after lifting it off the frame , it starts swaying .
     
  9. BR-549

    Well-Known Member

    Sep 22, 2013
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    Is your "crane" software controlled?
     
  10. MaxHeadRoom

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    Jul 18, 2013
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    So it would be the main carriage motion where it occurs?
    Max.
     
  11. t00t

    Thread Starter Member

    Jan 22, 2015
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    Nope my crane is controlled by a remote control .

    Yes , main carriage swings during lifting .
     
  12. BR-549

    Well-Known Member

    Sep 22, 2013
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    By main carriage, do you mean the part with the motor?
     
  13. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    If you pic and lift in the vertical then the reason is the carrier that moves too fast too soon.
     
  14. atferrari

    AAC Fanatic!

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    To whom are you replying Max?
     
  15. atferrari

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    Is there a chance to watch a short video of your crane in action?
     
    Last edited: Dec 10, 2015
  16. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The OP.
    I am thinking if the sway is on the main gantry direction, any short/rapid reversing in order to counter act will cause rapid heating of the motor?
    Max.
     
  17. BR-549

    Well-Known Member

    Sep 22, 2013
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    Some don't have brakes, it could be a normal action. Skill will be needed.
     
  18. crutschow

    Expert

    Mar 14, 2008
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    What "anti-sway" program are you referring to?
     
  19. MaxHeadRoom

    Expert

    Jul 18, 2013
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    This is one commercial system, they use an encoder, there is also cheap gyro IC's used (DigiKey) , but as the link shows, a VFD is used for the control of the motor.

    ". The system is mainly composed of PLC, frequency inverter and P + F encoder, which with low cost, using the automatic positioning anti-sway control technology, under the conditions of the general industrial crane with a maximum design speed of normal operation, compared to the crane does not use anti-sway control technology, swinging amplitude with load reduction at least more than 95%(actual sway angle less than 0.2 degrees), automatic positioning control accuracy of ± 2 mm."
    Max.
     
  20. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Max, I hope we all are talking about thee same thing. A video would put all of us in the same picture. Nice pun!

    What I mentioned, if not described, means that the crane (gantry or not), when moving in a certain direction, at a certain point could see the weight, further "ahead" so, to control (nullify) the pendulum that was created, the sole valid action is moving further ahead (NOT reversing) the point of suspension for it to catch up, coming quickly above the weight which, magically has no other option that staying where it is, because there is no more pendulum but a weigh hanging from the hook in a (more or less) perfect, vertical line. Having been seeing this for more years I like to recognize it is natural to me but I suppose it could be counterintuitive for anyone seeing this the first time.

    Even more, if you are watching the weight only, you will not even be aware of the above.

    Now that I think of it it, that is much easier to appreciate when you watch a gantry crane discharging / loading containers with you standing at the pier.

    Many modern ship's cranes have the speed limited by the weight the sensor detects so, even on purpose you hardly could impress excessive speed to the whole thing.
     
    Last edited: Dec 10, 2015
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