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Showroom 1/20 model of a 2DOF simulator for software and electronic tests

Discussion in 'DIY Motion Simulator Projects' started by petrus, Jan 6, 2015.

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  1. petrus

    petrus Member

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    I'd like to build a simulator but unfortunately, for the moment I live in an apartment and I don't have enough room for it. I can't get this project off my head so I am working on the part that doesn't require much room, the electronics.

    In order to test the electronics and firmware, I built a simple 1/20 scale model of a 2DOF simulator :
    model.jpg
    The black plastic parts are 3D printed, it uses cheap RC servos with the original electronics removed. The positioning is made by the microcontroller, it reads the servos potentiometer and drive the H bridges through a PID algorithm.

    The electronics is all custom designed and built, for the moment an atmega128 development board, LCD + buttons board and two H-bridges that I designed for a battle robot (it's the white one) :

    elec.jpg

    And here is the sketchup file if you want to print the model : www.xsimulator.net/community/attachments/maquette-zip.18160/?temp_hash=d59b586e19ea9e56baad290924809ec6

    Attached Files:

    • Like Like x 7
    Last edited: Jan 11, 2015
    petrus, Jan 6, 2015
    #1
  2. eaorobbie

    eaorobbie Well-Known Member SimTools Developer Gold Contributor

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    Neat , this should scale up very easily , have you been able to test run it with SimTools yet ?
    eaorobbie, Jan 6, 2015
    #2
  3. bsft

    bsft

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    • Agree Agree x 2
    bsft, Jan 6, 2015
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  4. petrus

    petrus Member

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    It is not meant to be scaled up, it's just to test the electronics.
    I still have some work to do on the firmware, but I already tested it with SimTools, it works well with the test sliders, but it's less responsive in live for speed.
    Btw, what is the scale for the different values ? For the angle it would logically be +/- 180° for +/- 100%, but for g forces 100% represent how many gs ?

    That's a nice compact simulator bsft, but I would like to build a joyrider-like simulator with wide motion angle (target : +/- 45°) and that takes much more space.
    petrus, Jan 7, 2015
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  5. bsft

    bsft

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    not sure about scales, cannot help there
    Ok, joyrider sim. cool
    bsft, Jan 7, 2015
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  6. petrus

    petrus Member

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    The lack of response I noticed in Live for Speed was just due to the global slider that was not set to 100%, once set to 100% it's super-responsive :)
    And I added two vibration motors :
    model_2.jpg
    A small one to simulate tire slip and a big one to simulate shocks.
    I use the traction loss value for the small vibrations, but in live for speed it only works in one direction. For example, if I start full throttle and brake heavily, the value barely change, but if I make a 90° turn, and do the same thing, it works fine.

    To drive the big motor, I use a derivative of the 3 acceleration forces, if this value exceed a threshold it drives the big motor for a certain amount of time.
    • Like Like x 1
    Last edited: Jan 11, 2015
    petrus, Jan 10, 2015
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  7. bsft

    bsft

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    good idea using the vibrator thingys , that would be a different idea to bass shakers
    • Agree Agree x 1
    bsft, Jan 10, 2015
    #7
  8. hooshang

    hooshang Active Member

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    good idea but deferent from bass shakers,and the question is which values suit these motors for vibration?
    hooshang, Jan 10, 2015
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  9. petrus

    petrus Member

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    Since the traction loss value doesn't work very well (at least in LFS), I now use the derivative of the sum of the 3 accelerations(absolute values) to drive the small motor, if this value exceeds a threshold it switch the motor on. This strategy works well for small vibrations like driving on grass and gear shifting but not for tire slip.

    The bigger motor is driven the same way, but with a higher threshold so only big shocks will trigger it.
    • Creative Creative x 1
    petrus, Jan 15, 2015
    #9
  10. welen123

    welen123 Member Gold Contributor

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    My Motion Simulator:
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    I'm very interesting with your mini simulation ,how to wiring the steering engine to the arduino uno ? I want to build it too .:):):):)
    welen123, Jan 18, 2015
    #10
  11. hooshang

    hooshang Active Member

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    @petrus
    as I learned so far bass shakers or butt kickers works with sounds like motors sound, and the RPM value can do
    the same with vibrators and this has nothing to do with grass.
    regards
    Hooshang
    hooshang, Jan 18, 2015
    #11
  12. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
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    • Like Like x 1
    noorbeast, Jan 18, 2015
    #12
  13. welen123

    welen123 Member Gold Contributor

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    • Like Like x 1
    welen123, Jan 19, 2015
    #13
  14. Archie

    Archie Eternal tinkerer

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    My Motion Simulator:
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    Weld a sledgehammer to an arm of a Worm Drive motor for "Impact" simulation...
    It could spin and whack the "frame"

    Or for monster vibration weld half a rotor disc to a worm drive shaft.
    Likely shake the house of it's foundations!

    :p
    • Funny Funny x 3
    Archie, Jan 20, 2015
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  15. bsft

    bsft

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    Yep, that 'll do it, aussie ingenuity
    • Funny Funny x 1
    bsft, Jan 20, 2015
    #15
  16. welen123

    welen123 Member Gold Contributor

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    [​IMG]
    I have build a RC model today,it looks will be OK,but there is somgthing wrong with the servo,I will check it tomorrow to find the problem, I used the RCModelDebugMode by @eaorobbie , hope i can fix the servo problem and run it.
    • Like Like x 2
    welen123, Jan 20, 2015
    #16
  17. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    Neat model @welen123.

    It would be helpful if you started your own thread, explained what the servo issue is and others can then help you get it sorted.
    • Agree Agree x 1
    noorbeast, Jan 20, 2015
    #17
  18. petrus

    petrus Member

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    I traced some curves using sway, surge and heave values while driving a straight line on road and grass.
    road :
    road.jpg

    grass :
    grass.jpg
    As you can see on the last curve, by choosing the correct threshold, the vibrations can be turned on during gear shifting and driving on grass and not while driving on the road. The big spikes at the en are when the car hit the wall :)
    • Like Like x 1
    • Informative Informative x 1
    petrus, Jan 20, 2015
    #18
  19. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
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    So what were you using as the base game for your testing @petrus?
    noorbeast, Jan 21, 2015
    #19
  20. petrus

    petrus Member

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    I used live for speed
    petrus, Jan 21, 2015
    #20
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