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3 DOF Motion - PIVOT

Discussion in 'New users start here - FAQ' started by Runxax, Feb 27, 2009.

  1. Runxax

    Runxax New Member

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    Hi all,

    Im very confused about the parts to make the PIVOT on Motion platform 3DOF.
    Take a look at picture and, my questions is:

    What and where I can buy that?

    Best regards
    Rui

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    Runxax, Feb 27, 2009
    #1
  2. egoexpress

    egoexpress Active Member

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    The area you've marked on the pic are two parts. The upper part is a cross(cardan)-joint, and the lower part is a shock absorber (probably from a car or a truck).

    You will be able to get both parts on the car junkyard for cheap.

    Regards
    egoexpress, Feb 28, 2009
    #2
  3. Runxax

    Runxax New Member

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    Tks for answer.
    I already went to junkyard, and brougt the cross(cardan)-joint!
    But about shock absorber, im still confused....
    My question is about rotation of the shock absorber...let me explain bether.
    As you can see on the first picture the shock absorber have striations, and all shock absorbers that I saw on the junkyard dont have striations.
    So you can rotate one of the ends (see new picture).
    Do you think that will cause me any problem?
    Take a look to this video to... http://www.youtube.com/watch?v=_R50re8i ... annel_page

    Tks
    Rui

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    Runxax, Feb 28, 2009
    #3
  4. R-eng

    R-eng Member

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    Normally dampers can rotate freely one end to another. It is nothing more than a rod with a piston attached, which then moves longitudinally inside a cylinder. This can freely rotate relative to each other, although with some friction and resistance.

    Unfortunately, in this setup there is also a spring involved. It is not designed to rotate easily, and it will not with a load on top. This is only a 2.DOF support which can tilt in 360deg. You would need to place it on a horizontal bearing support to allow rotation and 3.DOF.

    R-eng
    R-eng, Mar 2, 2009
    #4
  5. wannabeaflyer

    wannabeaflyer Active Member

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    HI guys not advertising ians (Buggies built for fun) site but i think he has added an anti rotation device to the back of his simulator called Sarrus link ( Think i spelt that wrong ) basically it allow motion up and down while pivoting around a central axis without the twisting motion that you would get if you just used a plain Shock damper without the splines. ( on the prop shaft in your picture ) again not an advert for other sites just that he used some easy methods for his platform which may or may not help i picked up a lot of info trwling the net different ideas but leading to the same goal so we builders choose the methid that easiest/cheapest for us help with our projects :D
    wannabeaflyer, Mar 2, 2009
    #5
  6. Saviosso

    Saviosso New Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    these splines are normally found in a car part, an example is the front transmission bar, as it needs to move, depending on the terrain, it can elongate and shorten and at the same time shift the traction from the engine to the wheels.
    Saviosso, Jun 12, 2021
    #6