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4DOF Based on the work of SeatTime

Discussion in 'DIY Motion Simulator Projects' started by Blugreen, Aug 12, 2015.

  1. Blugreen

    Blugreen New Member

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    My Motion Simulator:
    6DOF
    Hi all.

    I have spent many many hours as a voyeur of this forum. I initially started with wanting to run before crawling and build a 6DOF for Helicopter Sim training (currently have 50hrs of real heli training and I think a sim would be a help with the processes more so than the flying) and some iRacing but decided to start with a slow jog and build a rig heavily based on the work of @SeatTime.

    The components will be as follows:
    4x MD Worm Drive Motor 12V/24V 200W, 180 RPM, 20Nm Torque
    4x JRK 12v12
    4x 12v 40A Lead Strip PSU's

    I am at this point thinking about putting the surge table on some Linear Rails and use a rack and 40T Pinion Gear (CNC components) on the motor to facilitate the movement. My calculation is that as the pinion gear has a circumference of 84mm I should get around 252mm per second of movement. Is that enough?

    I am still working out doing the drift but I may use another rack and pinion noting that the rack will have to be curved.

    Can I please ask what people think is a good amount (distance and speed) of Drift for Racing Sim?

    A recommendation/link to Hall Effects Sensors would be great also.
  2. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
    3DOF, DC motor, JRK
  3. Pit

    Pit - - - - - - - - - - - - - - - - Gold Contributor

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    My Motion Simulator:
    DC motor, Arduino, 6DOF
    Hi @Blugreen I am building a table using a 20t gear (8.8cm diameter) and get a speed of max EDIT!! 36cm per second for a race simulator. Adding the surge speed of the seat produced by the 2DOF the first two seconds I get additional 2 cm per second. We can't simulate real speed due to room constrains it is more important to feel the mass which will be moved from "zero" to a short distance rather then the effective speed of a car. Sit down on a rolling office seat and ask someone to push you forward, if possible within a defined speed f.eg. 20cm per second. The most immersive moment is at the very first beginning while accelerating. When you reach the final speed you won't feel anything more.
    • Agree Agree x 1
    Last edited: Aug 13, 2015
  4. Blugreen

    Blugreen New Member

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    Thanks @noorbeast for the links.

    Also, thanks @Pit for the reply and advise. Makes sense.
  5. Pit

    Pit - - - - - - - - - - - - - - - - Gold Contributor

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    My Motion Simulator:
    DC motor, Arduino, 6DOF
    I did a mistake, I multiplied the diameter * U/min (cycles per minute), but I have to multiply the circumference. Using a 8.8 cm gear (diameter) I get a speed of 36cm per second (80 cpm * 27 / 60) - hope I am not wrong again?! :)
    Last edited: Aug 12, 2015
  6. SeatTime

    SeatTime Well-Known Member

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    My Motion Simulator:
    AC motor, Motion platform
    Hi @Blugreen , all the best with your build, are you referring to my old 5 axis sim? I was very happy with that setup, although I would have liked a working washout filter for the surge table. I don't know your background but there is still allot of work in building a working 4DOF (I would not call it crawling or even a slow jog;)).
    • Like Like x 1
    • Friendly Friendly x 1
    Last edited: Aug 12, 2015
  7. Simon_lebel

    Simon_lebel Member

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    My Motion Simulator:
    2DOF, DC motor, JRK, 4DOF
    I will follow your project as i am building something similar. Have fun building it, that what it is all about in the end!
  8. Blugreen

    Blugreen New Member

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    Hi @SeatTime.

    Yes I was referring to your 5DOF.

    I luckily have a MIG, Oxy, a small lathe, a Mill Drill etc so the physical construction should be ok.

    What did you see as the hardest part of that build?

    Your 6DOF actuators look awesome. I am following that build with interest.
  9. SeatTime

    SeatTime Well-Known Member

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    My Motion Simulator:
    AC motor, Motion platform
    Finding the patience/time to ensure everything was right before moving forward while putting it all together . No different with my current sim - 8 months and counting:rolleyes:.
    • Like Like x 3
  10. Blugreen

    Blugreen New Member

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    Hi @SeatTime. I have spent much of today on AutoCad designing my rig in 3D (static). I find it best for discovering if there are any issues with spacing between objects.

    Can you recommend the crank arm lengths that you used for the 2 shoulder motors?

    TIA

    Mark
  11. Blugreen

    Blugreen New Member

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    My Motion Simulator:
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    Today I purchased the following...now to wait for all the boxes to arrive.

    4x Motors
    4x JRK's
    4x Hall Effects Pots
    4x PSU
    2x Linear Rails and bearings
    4x Flexible Couplers
    4x Rod Ends
    4x Adjustable Leveling Feet
    1x Other little bits and pieces.

    Can't wait to get stuck into building the rig.
    • Like Like x 2
  12. SeatTime

    SeatTime Well-Known Member

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    My Motion Simulator:
    AC motor, Motion platform
    I used a crank arm with a few holes in it, but settled with 65mm. Although this will depend on how/where it is connected to the seat.
  13. Blugreen

    Blugreen New Member

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    A quick update as to progress.

    Received the motors, JRK's and hall effects sensors today.

    Picked up the steel today also. I am hoping to start the frame this weekend.

    I also decided to go the Oculus Rift DK2 route so ordered one during the week.

    Now just need to find a wrecker that doesn't think his tail shafts are gold plated.
    • Like Like x 1
  14. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
    3DOF, DC motor, JRK
    Have you finalised the design and can you post a sketch of what you plan to build?
  15. Blugreen

    Blugreen New Member

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    Hi @noorbeast

    Here are some images from the initial design.

    I have gone for a full moving rig and I am sure the design will change a little during construction.

    The wheel and pedal mounting will be a design on the go. I have made the control mounting sliding which then changes my CG. I have devised a way to easily adjust the top platform to adjust the CG and I also have a design in mind to be able to then adjust the push rod attachment point as that needs to be lengthened/shortened if the seat platform gets moved.


    [​IMG]

    [​IMG]

    [​IMG]
    • Like Like x 2
  16. WhiteGoblin

    WhiteGoblin Member

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    My Motion Simulator:
    2DOF
    Looks like that rig will be insanely heavy. that's 1" tubing all the way around?

    My seat is mounted very similar to yours with a shoulder bar connected via a tube down the center. One potential problem is that the seat will flex and hit the shoulder bar during surges/pitches. I ended up using rubber bumpers to soften the jolt/noise you get.