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rotary actuator 6 DOF designs

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by Jamie Wilson, May 5, 2021.

  1. Jamie Wilson

    Jamie Wilson New Member

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    Hi,

    I've been a lurker on these forums for quite some time, but am getting serious about starting a project.

    I'm thinking of going with a 6 DOF rotary Stewart platform, as this seems an easier build than a linear one. With less ongoing maintenance and potential repairs. ( DIY actuator, not something like a PT actuator which I would expect to be very reliable)

    My use is mostly flight sims, but I would like to try my hand at some racing games as well. I own a few, but never really used them due to only have VR capability with no monitor on my current set up. Many titles are difficult to unusable without some monitor interaction through menus.

    I plan on using 80ST AC motors with 50:1 gear reduction.

    My questions are.

    1. Is this sort of design good as an "all round" simulator ? 70/30 flight/racing

    2. Stewart platform has a high CofG compared to many of the sunken linear actuator designs. Where does this offer and advantage/disadvantage ?

    3. What speed, throw and angles are desirable. I see some rigs with huge travel, but then read "less is more". I'm guessing more travel and angle for flight sims, less and faster for racing ?

    4 Am I simply off the track in the weeds, and should be rethinking the whole idea ??? :cool:

    Thanks for reading.


    Cheers
    Jamie
  2. Ads Master

    Ads Master

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  3. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
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    A 6DOF is a good all round rig.

    A rotary 6DOF CoG can be sunken, it is a matter of design.

    Less is more in terms of large axis angles in VR, but what does matter is precision of movement, the latter relates to good design adequate speed and refined tuning.

    A 6DOF is a somewhat complex and expensive first project. Do plenty or research, start a build thread and post actual design and parts lists before buying anything, so members can give feedback and guidance, which will save you a lot of time, frustration and money.
  4. Jamie Wilson

    Jamie Wilson New Member

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    6DOF
    Thanks for your reply noorbeast! Much appreciated.

    I've tried to read as much as I can on these and other forums. Hopefully a 6 DOF isn't biting off too much for me. I do have a friend that is very good with engineering farm equipment and has offered to build what ever I need. I just have to do the hard part, pay for it!

    I look forward to sharing my work if and when we get started.

    Cheers
    Jamie
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  5. Gadget999

    Gadget999 Well-Known Member

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    My Motion Simulator:
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    I see some rigs with huge travel, but then read "less is more". I'm guessing more travel and angle for flight sims, less and faster for racing ?

    i think that sum it up - I suggest you search some of the sims used for flight and some used for driving and conpare designs

    It may be possible to adjust the gearing of your sim and the lengths of the lever arms to swap between distance and speed

    if you move the piviot points on the stewart platform closer together you will get more twist and greater angles of movement
  6. Jamie Wilson

    Jamie Wilson New Member

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    Thanks Gadget999 all makes good sense.
    Great build btw.

    I started another topic, as I am also considering a linear setup.

    Cheers
    Jamie
  7. sallerding

    sallerding New Member

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    Hi Jamie

    I have just started my 6dof rotary build mainly for flying but also general purpose. Most large items have arrived (80st motors, aasd15 drivers and planetary gearboxes) it is just down to completing and welding the rig and tortuously waiting for some specialised components from China.

    There are many great examples on the forum but the one that inspired me was by motion4sim. He has some good videos with flying to see how it works as well as with cars. He also has a controller and there are videos that provide a pretty good example of range and speed for his rig that are worth looking at. Best of luck with your journey. It took me two years of reviewing stuff on this forum before finally biting the bullet but I am happy with my decision to go rotary. How happy will be tested when it’s up and running
    Last edited by a moderator: May 13, 2021
  8. Jamie Wilson

    Jamie Wilson New Member

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    6DOF
    Hi sallerding,

    Thanks for your reply.
    Great to hear you have begun your build. Do you have build thread ?

    Yup, I agree Motion4sim's rig is impressive and looks like it moves great on the videos. I was actually ready to start building pretty much the same thing. However I really wanted to try my hand at building a linear actuator design. I'm not sure if it is a simpler task or not. I feel the cost of parts is a little lower. Those gearboxes don't come cheap.

    I just ordered my 80st motors and 1610 600mm ball screws last night. Along with some other bits.

    Haven't settled on a controller yet. Although Motion4sim's looks great.

    Will you use your simulator for both flying and racing ?

    Sounds like our journeys to here have been similar. I think it's been about 2 years to get to this point also!

    Keep in touch

    Cheers
    Jamie
  9. sallerding

    sallerding New Member

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    My Motion Simulator:
    6DOF
    no build thread yet. Will put together once all items received.

    I expect that 80% flying use and 20% racing/general. Yes will keep in touch with what you’re up to. Thx
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