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6 DOF compact Sim with rotary actuators

Discussion in 'DIY Motion Simulator Projects' started by Motion4Sim, Jun 14, 2020.

  1. sallerding

    sallerding Member

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    Hi. Looks like you’ve got it working nicely. I see you changed the upper platform from steel to aluminium sections. Was that just to do with weight and how has that worked for you? Thx
  2. T R Para

    T R Para i make stuff up

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    @sallerding It has worked out really well. I do not know if you are familiar with Grigorys' 6DOF thread but that was the one that got me interested in the basic design. He had mentioned that it was important to keep the weight down on the platform. I cannot weld Aluminum and having a shop do it is very expensive. So I bought a 4meter length of 40mm 80/20 extrusion. I was unable to find a source of 60 deg corner brackets and just cut those you see from aluminum plate (plates are on the top and bottom)
    The platform is held together with a lot of bolts and is extremely stiff. The design also allows the connection point of the Hiem Joints to be adjusted by about 100mm.
    The picture of the steel platform is not mine but borrowed from a sim forum that appears to have been abandoned. Here is a link to that forum.
    It is a bit dated but then in todays world 2 years ago is ancient history !
    I did try to contact the author of the build but he never replied.

    https://motionsim.freeforums.net/thread/176/dof-step-diy-project-blueprints

    Always happy to help fellow Sim-mers..
    • Like Like x 1
  3. Motion4Sim

    Motion4Sim Member

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    Hey nice to see your progression really great. corona sucks. I have everything ready. will go online today with the sale. I still have a couple of fully functional prototype controllers that I will hand over at a reasonable price I will write in about 12 hours.
    the spike filter has been completely redesigned and is the best I've ever had. See you.
    health and freedom for you all
  4. sallerding

    sallerding Member

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    Thx. Yes I can see from the number of bolts that it looks pretty solid without much movement. Novel way of connecting the universal joints also. I take it it has undergone human trials (not just rabbit trials :)) and the aluminium holds up under human weight and under reasonable stress. Do you have the dimensions of the upper platform you can provide? Thx again
  5. T R Para

    T R Para i make stuff up

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    @sallerding Yes it is very solid. I weigh just over 100kg and no problems. The 40mm extrusions are probably over kill. There are only 3 different sized pieces to the platform x 3 so the measurements are pretty simple. All the pieces were cut on a 12" powered Miter saw with a metal cutting blade set at 30deg. I threw in a bunch of other pictures. (I like pics):think

    Attached Files:

    • Like Like x 1
    Last edited: Nov 23, 2020
  6. Motion4Sim

    Motion4Sim Member

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    :thumbs:thumbs
    very cool i had similar adapters milled so that i got more range in the ball joint

    i use m24 balljoint really oversized but i got a large angle and i can move now all position without
    mechanical limits.

    will send some more details of my rig next days

    Attached Files:

    • Agree Agree x 1
  7. T R Para

    T R Para i make stuff up

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    WoW those are pretty massive. I bought mine off E-bay and they are only 13mm (1/2") and still cost me $200 USD for a set of 6.
    But the best part was watching me bend the pushrod tubes. I bought one of the $130 USD Chinese benders off Ebay and it was very hard to bend the 25mm steel tubes. But I got through it OK.:blush

    Attached Files:

  8. sallerding

    sallerding Member

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    Great!. Thank you
  9. sallerding

    sallerding Member

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    Thx motion4sim
  10. xeg1101

    xeg1101 New Member

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    I am curious why is the bend on the rods needed? Does it provide more angle of motion as compared to straight rods, or is there some other reason? By the way @T R Para ,
    a. what motor/servo combo did you end up going with?
    b. On full load with driver on seat, upon direction reverse, how much power does a motor use?
    c. Does it ever trip your breaker or is power draw not that much during normal use?
  11. T R Para

    T R Para i make stuff up

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    The bend in the rods are not needed. When I was building my platform I had no idea what I was doing.
    So I tried to get others to help me out with their drawings/dimensions. I found it impossible to get a set of working plans to build my platform.

    The bent rods are the idea of the starter of this thread. I believe they allow a smaller top deck. This can give you increased angle of throw.
    As it turns out it worked well or me. I use my sim with FS2020 almost every day. And it has held up.
    The rotary actuators have required zero maintenance since first use.

    The motors.
    https://www.ebay.com/itm/1000W-4NM-...CNC-Milling-/265377305239?hash=item3dc9b85297


    Gear boxes. Nema 32 20:1 ratio 2 stage.
    https://www.ebay.com/itm/Nema32-Ser...t-19mm-/265150190173?var=&hash=item3dbc2ed25d

    I do not have a piece of test equipment to check peak amp draw.
    I am running them off a 220v 40amp circuit.. And that is massive overkill.

    The motors do not draw that much power. I believe I could've used a 120v 20amp line.
    3 years ago nobody knew much about these motors.
    A lot has happened since then.
    Now they are the goto motors.

    Here is a short video I made. a while back.
    • Like Like x 4
  12. xeg1101

    xeg1101 New Member

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    @T R Para thank you for the info, that was very helpful.
    Do you think it would be a good idea to build the bottom frame out of aluminum extrusion (4040 or maybe 40-4080?), similar to how you build the top frame (where seat mounts)? Or would welded steel be the better choice
  13. sallerding

    sallerding Member

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  14. Motion4Sim

    Motion4Sim Member

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    @xeg1101
    That's a good question . at the beginning of my development i naturally worked with straight connecting rods. It turned out that if I choose the fastening points closer to the upper platform, I can generate more rotation, but the construction of the lower platform was in the way. because it can't get any smaller, i finally bent the rods.

    I measured my power consumption at 220v, the motors pull 6 x 750W approx 300-400 watts peaks definitely go up to 800-1000 watts, but I think 16 A fuses are sufficient. my friend even only uses 10A fuses for all motors. I use a time relay for the start so that the high starting current for charging the capacitors does not trigger the fuse. so first 3 , and the other motors are not switched on 1 second later.

    @sallerdings
    my rods are 3mm thick and 28mm in diameter
    • Like Like x 1
  15. T R Para

    T R Para i make stuff up

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    @xeg1101 I built the lower assemble out of steel because I could weld it myself. As it turned out it was a good choice. The extra weight makes for a stable base. You do not want this thing moving around on you.:):):)
    A base made from extrusions would work also. The cost will be much higher as all the connecting fittings will be expensive.
    The choice for the aluminum top deck was because I had already purchased the 4040 extrusion. You could do it in steel and it would be fine. Some guys commented on the fact that the less mass you have to move around the better.

    @sallerding Here in the US we have to buy in imperial measurements. So the tubing was 1" od by >.065" wall cold rolled steel. It was amazing how difficult it was to bend with my Chinese Ebay tubing bender. Had I chosen a thicker wall tube I would've never bent it. It would of had to be done at a fabricating shop.
    The tubing I used is plenty strong.
    Steel is very strong at a reasonable cost.
    • Like Like x 1