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3dof using 4 linear electromagnetic actuators

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by borex, Nov 24, 2020.

  1. borex

    borex New Member

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    Hi so I'm new to sim racing and had an idea to build my own motion sim. I don't have an engineering (or electronics) background so forgive me if this question is stupid. Would it be possible to just have a platform controlled by 4 linear electromagnetic actuators (in all 4 corners)? This design could be incredibly cheap because it requires no moving parts (just an electromagnet, rod, gimbal and permanent magnet). Also all parts could be built with off the shelf parts (wire, magnets, metal rod etc.) Obviously I would need to build/buy a controller to control the voltage to the actuators (and would probably require very high voltage to power). Benefits would be very fast power delivery to the actuators and cheap build cost.

    My question is what would be the pitfalls of a design like this and why has nobody (as far as I can tell) done something like this?
  2. BlazinH

    BlazinH Well-Known Member

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    There's a thread here where it was being attempted but I believe it's been abandoned since I haven't seen anything new lately.

    I think a major pitfall would be dealing with inertia since there's no gearbox to increase torque.
  3. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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  4. adgun

    adgun Active Member

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    Most linear/shaft motors arent that strong, you need a lot of current
  5. MarkusB

    MarkusB Well-Known Member Gold Contributor

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    I think I remember a guy here in the forum who had developed such kind of actuators and built a 6 DOF rig with them. I even remember a video of the rig in action and pictures of the actuators where you could see the wire coils around the shaft. However, I was not able to find anything about it anymore.
  6. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    • Winner Winner x 1
  7. MarkusB

    MarkusB Well-Known Member Gold Contributor

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  8. borex

    borex New Member

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    Thank you! This was exactly what I was thinking except I was thinking of using springs to offset the weight of the machine/ myself but using pneumatic is even more interesting.

    In the video(s) you can see exactly how this design is superior to most other 6dof builds (in terms of jerk vibration capabilities), while using almost no complex moving parts.

    Check out the link above. Basically you can use either springs or a different force (in this case pnematic pressure) to balance the weight of the rig and the person sitting in it. After that it takes very little current to move the weight up and down using the linear motors.
  9. RacingMat

    RacingMat Well-Known Member Gold Contributor

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    @noorbeast is a sniper!

    You got it! You could of course do the whole thing with just the magnetic side but it would drive the cost and power up significantly. So its a bit of a hybrid approach we are taking.