Solved Suspension and wheel instability.

Discussion in 'Mod Support' started by TechMechanic, Sep 18, 2018.

  1. TechMechanic

    TechMechanic
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    This go-kart has the rear suspension in place, however the tires explode even with no psi selected. Almost all of the suspension is tunable but no matter how hard I try I cannot make the suspension and wheels stable.
     

    Attached Files:

  2. aljowen

    aljowen
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    So I think the issue is to do with your BeamSpring values on the vehicle.

    13,000,000 is rather high. I would suggest setting all of your chassis beams to have a BeamSpring value of 5,000,000 to start with, then you can fiddle from there.​

    That should get rid of a lot of the shaking.


    As for the suspension, there is something clearly wrong with it's design, I haven't looked into that though since I don't know what you are going for or whether that is on your todo list or not.

    Your BeamSpring values on the suspension springs are also set way to high.



    Its not done yet, but I have been working on the following wiki page that might be of use for you: https://wiki.beamng.com/JBeam_Physics_Theory
     
  3. TechMechanic

    TechMechanic
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    For the chassis itself, all of the values are 1,900,000 for beamspring. Should I just lower the suspension beamspring settings?
    --- Post updated ---
    "13,000,000 is rather high."
     
  4. aljowen

    aljowen
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    Crap, you're right, I think I meant the suspension arms :p

    Typically you would go quite high on suspension arm values, but the 13mil that yours are at is too much for the jBeam design that you have.
     
  5. TechMechanic

    TechMechanic
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    I'll try editing that then and I'll respond if there are changes.
     
  6. TechMechanic

    TechMechanic
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    After removing the high values the wheels are more stable, however the wheels still deflate and the wheels are not straight, would this be caused by too high beamspring as well?
    --- Post updated ---
    The newer file:
     

    Attached Files:

  7. aljowen

    aljowen
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    Currently looking through it. Here are some suggestions to make debugging easier:
    • Change your "cameraExternal" section so that "distanceMin" is 1. This will make it much easier for you to debug things because you will be able to see them much closer.
    • If you aren't already, give slow motion a try. It might not help in all cases, but its really useful for seeing what is actually going on when weird stuff happens.
    Some issue that I have noticed that could do with some work
    • Your wheel nodes are much narrower than the wheel, this can cause them to wobble and vibrate while going round corners, due to leverage on each side.
      • Move "rw1r" further out, and "rw1rr" further in, repeat for each wheel. 0.34 and 0.16 would be good starting points. You could go wider for better lateral wheel stability.
    • The same is also true of your rims and tyres. Your tyres are far wider than the rims, generally I try to make the tyre width ever so slightly narrower than the wheel rim, but other modders may have their own ways of doing that.
      • So having the rims be 0.215 wide seems appropriate given the tyre width
    • Your tyres are too light weight.
      • The best solution would be to adjust the "//tire options" section until you get something that doesn't explode (by reducing some BeamSpring values)
      • The easy solution is to make them heavier by adjusting the "nodeWeight" of the tyres
    The attached file has the above already "done", however I took the lazy routes for the purposes of debugging things quickly, so you should go through the things above and adjust them to your preferences. Not to mention things are still a little shaky because it takes a bit of time to tune these things properly.

    As for the suspension collapsing in on itself. It looks like you are going for a double wishbone setup, however you currently only have a single beam connecting the wheels to the suspension arms, hence everything flops all over the place. Aka, your wheels aren't attached to the chassis in any meaningful way.
    • So essentially you just need to connect the "SUSBR4", "SUSBR5", and "SUSBR2" to both "rw1rr" and "rw1r".
    I haven't done this bit because its just connecting up beams, and it is your suspension system to design after all :)
     

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  8. TechMechanic

    TechMechanic
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    Thank you so much! :) However there is one final question; my gears now are reversed, reverse is drive and drive is reverse. Is there a fix?
    --- Post updated ---
    NVM, I found it out, again thanks for helping out.
     
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