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Question Please help with Sim calc calculations for my 2dof sim design

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by OvaisSaand, Dec 25, 2021.

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  1. OvaisSaand

    OvaisSaand New Member

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    My Motion Simulator:
    2DOF, 3DOF, Motion platform
    Hello,
    I am currently in the designing stage of my 2dof sim and have made a rough 3d sketchup model

    I am bit confused with sim calc because it shows a shoulder mounted design while my design is foot/knee mount and so the X Y Z axis are confusing me as well as the motor angle , ctc rest angle, max angle and current angle. Some clarification and guidance would be help full.

    Also need more details for recommended output values for pitch force, rotation, travel and torque
    As in the FAQs I only read the recommeded motor speed and rpm and basic linear speed and forces
    Please forgive me if I've missed it.

    I went through the SimCalc Math Reference Sheet and to be honest it went through my head.


    The motor i have choosen as a starting point is Worm Drive Motor (12V/24V 200W, 180 RPM, 20Nm Torque) from Motion Dynamics

    Below I've added my design and some dimensions to add to sim calc and also added a sim calc screen shot for the value I added that I think are NOT correct
    All Dimension in Sketchup are in cm and from the center of the pivot

    Please click on pictures to zoom

    Many thanks!

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
  2. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
    3DOF, DC motor, JRK
    Ignore the SimCalc shoulder mount image, it is there only for reference.

    For CTC 50mm is likely a more reasonable for a full frame, you can allow for higher with levers drilled for various CTC, but start conservatively.

    Lever angles over about 38-40 degrees up and down become really inefficient with respect to effective torque utilisation, so I have used that below.

    I hope I have got your dimensions correct, but you really need to double check them:

    SC1.jpg
    SC2.jpg
    • Like Like x 1
  3. OvaisSaand

    OvaisSaand New Member

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    @noorbeast

    Thanks for the reply I see the first mistake I made in simcalc was using mm value in motor and mount position I cant believe I missed that :roll

    Okay I'll make a lever with different CTC holes to play around when the sim is complete

    About decreasing the lever angle, how should I go on about that in my design should I move the bracket the rod is connected a bit back or should I make more holes in the bracket to decrease the angle, or I can move the motor a bit back and get the same results
    I've attached a picture for you to get an idea of what I am talking about

    [​IMG]


    I think dimension are correct now because the outputs now actually make sense
    Talking about about output what do you think the recommended pitch rotation and roll rotation be in degree?

    Also do you have any recommended design changes I should do ? I've never driven a sim besides the arcades ones, so have no idea what is enough for me. This will be mostly used for racing

    Again thanks alot for the help!!!
  4. OvaisSaand

    OvaisSaand New Member

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    My Motion Simulator:
    2DOF, 3DOF, Motion platform
    So I finally played around with simcal and finally settled on the design I want
    and just need to start working on collecting all the parts to build my sim :thumbs
    I've attached picture below of my new design and simcalc results
    [​IMG]

    [​IMG]

    [​IMG]
  5. imajavaid

    imajavaid Member

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    My Motion Simulator:
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    Can you kindly share the dimensions of your motor
  6. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
    3DOF, DC motor, JRK
    Time will tell but I think your CTC is a little large. I would suggest start with 50mm and take it up or down after actual testing, depending on the heat the motors generate.
    • Like Like x 1
  7. OvaisSaand

    OvaisSaand New Member

    Joined:
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    Student
    Location:
    Karachi, Pakistan and Brighton, UK
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    My Motion Simulator:
    2DOF, 3DOF, Motion platform
  8. OvaisSaand

    OvaisSaand New Member

    Joined:
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    My Motion Simulator:
    2DOF, 3DOF, Motion platform
    Yup just like you said I'll add holes with different spacing and play around with each one to see , which is working the best
    • Like Like x 1