Unsolved NEED HELP FROM EXPERIENCED MODDER: Tuning my suspension for the Maluch Remastered mod

Discussion in 'Mod Support' started by Agent_Y, May 28, 2021.

  1. Agent_Y

    Agent_Y
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    So as some people know, I have been working on completely redesigning the Jbeam structure of the Maluch mod for a bit over a week now. So far I have added the most necessary parts to make it drivable, and it's all looking good so far except one thing: the suspension.
    1.png

    Most of the Jbeam of the car is based on a heavily modified Piccolina Jbaem. I could reuse about 2/3 of the nodes and beams it had and moved them around to fit the shape without causing any structural stress, but I haven't yet modified any deform values, the car needs to be more complete before I crash test it. The other 1/3 is stuff I had to Jbeam from scratch and add to the structure. This includes the suspension. It was the first suspension I have ever made in my life, prior to making it I had never used bounded beams or L-beams before, I couldn't reuse the one from the original mod because it was extremely inaccurate, and there's also the fact that the suspension of this car is unique and couldn't be swapped from another car. Also the car is too small to get over most of the suspension testing trails on Gridmap properly so it's not easy to just test what is wrong. Despite all these factors I got it to somewhat work, but it definitely needs to be improved as it has many problems.
    2.png

    I need help from someone who has EXPERIENCE with tuning suspensions. I don't think a random person can improve it as it's likely quite a bit harder than tuning a more standard suspension. By tuning I mean not only adjusting the spring and shock values, but possibly changing a lot of other things that might be causing issues, like moving/adding/removing nodes or beams, and also adding missing customization options. Now let's talk about the suspension itself and what needs to be fixed in it:

    FRONT: INDEPENDENT SUSPENSION WITH A REVERSED TRANSVERSE LEAF SPRING ALSO ACTNG AS THE LOWER ARMS
    3.png

    This kind of suspension is unlike anything that has been previously represented in the game. The closest we have is the LeGran/Wendover IRS, except in that one the leaf spring is straight and separate from the lower arms. It wasn't easy to get this working, at least for me because I had no previous experience. I based the leaf spring on the Pigeon ones, except I had to "reverse the mechanism" because here the middle is in place and the ends are moving, while in the Pigeon it's the opposite. That's why I needed an extra uncollidable node for the L-beams that sticks out at the bottom, the Pigeon has it between the leaf spring and the frame. When I first got it to work, it was far from perfect. The lack of lower arms was making the structure very unstable, so I added an extra stiffening structure below the arms. It was also very wobbly so I needed damp helper beams with quite a lot of damping. It was a challenge to figure out what needs to be fixed and how, and the spring and damp values of each part of the leaf spring weren't easy to get right.

    WHAT STILL NEEDS TO BE FIXED:
    • Under hard braking (relatively, as the car has weak brakes), the wheels move to the back. Similarly when braking in reverse they move to the front but not as much.
    • There is beam stress present on the leaf spring, the Pigeon has the same problem but not that much.
    • Wheel hubs can sometimes explode but it's very rare, could be related to the above issue.
    • The car pulls a bit to the left, which is caused by the weight distribution being left-biased (same as in real life, but the real car doesn't pull so it can be fixed).
    • Steering gets off-centered easily, even to the point of inverting a whole wheel, despite having limiters to prevent this, no idea what is going on with it.
    • Leaf spring values need improvements for better driving.
    • Shock values need improvements similarly.
    • Camber and caster adjustment options need to be improved, missing toe and left/right trim adjustments need to be added.
    • The car needs rally versions of its suspension components with realistic and adjustable values for rallying.
    • Probably some more issues I missed...

    REAR: INDEPENDENT MULTI-LINK SUSPENSION WITHOUT ANY UPPER ARMS, WITH VERY SHORT COIL SPRINGS AND SHOCKS
    4.png

    This suspension was way easier to implement at first due to the structure being way more generic. However it has proven to be way harder to tune and adjust, due to the shocks and springs being incredibly short. They are only 14cm long in game, and I already assumed they are as long as the model possibly allows. For comparison the front shocks are 27cm long, almost twice as much! I assume the reason they are so short is because the fuel tank is located right above the left arm and otherwise it could hit it... Who designed this??? Anyway, I had to retune all the spring and shock values many times, they needed the biggest rework when I added the engine, and I'm still far from happy with them. Initially the shocks and springs would extend way too much out of their normal size, even when driving normally, I had to lower the hard travel limit long bound all the way down to 0.01 to fix it. Now it's better but there are other problems...

    WHAT STILL NEEDS TO BE FIXED:
    • There is not enough damping somewhere and the wheels wiggle up and down mid air, but increasing the shock damping is not possible as it causes a lot more suspension stress everywhere.
    • There is suspension stress by default, even reaching the wheel connector beams.
    • Sometimes (reproducable easily by drifting for a while) the suspension can just "bend in" and it causes a ton of stress and weird forces. I tried many ways to fix it but all failed.
    • Coil spring and shocks values need improvements for better driving.
    • The car needs toe and camber adjustments, which can be difficult to implement as the compression of the suspension directly affects these due to lack of upper arms.
    • The car needs rally versions of its suspension components with realistic and adjustable values for rallying.
    • Probably some more issues I missed...

    5.png
    I haven't yet decided if I will post the unfinished mod file here or to contact whoever is willing to help and only give it to them. Either way it will remain unfinished until someone helps with the suspension. I will be really thankfull for that, and so will be the rest of the people working on this mod.
     
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  2. LucasBE

    LucasBE
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    here's a quick idea for the front suspension :
    beams.png
    I think using 2 center nodes instead of 1 would greatly improve rigidity, kind of acting like lower wishbones.

    As for the L-beams, it wouldn't really be practical here. You'd have to use torsionbars setup like this instead :
    torsionbars.png
    Essentially just "Z-shaped" anti-roll bars, acting as the leaf spring.
    Code:
    ],
        "torsionbars":[
            ["id1:", "id2:", "id3:", "id4:"],
            //--front leaf spring--
            {"spring":"$=$spring_F / 5", "damp":0, "deform":9000,
            "strength":200000},
            ["fa1r","inboard1","inboard2","fa1l"],
            ["fa1l","inboard2","inboard1","fa1r"],
    ]
    spring values would probably have to be tuned as torsion bars have a tendency to become unstable quite easily.

    Overall I think that redoing it this way would fix some of your issues. I'd be happy to help with tuning/jbeam as well :)
     
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  3. Agent_Y

    Agent_Y
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    That's a really good idea with the torsion bars, I haven't quite learned how they work yet but I guess I have to now, I can imagine it working better than the L-beam already! And if you want to help with the tuning, should I send you the file somehow after I do the torsion bars?
     
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  4. LucasBE

    LucasBE
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    sure, you can DM me on discord or just send a drive link in a forum DM, it's up to you
     
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  5. EunosRoadster69

    EunosRoadster69
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    I really gotta learn this kind of stuff. Looks like funnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn:(
     
  6. S.Ali.M

    S.Ali.M
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    Please avoid posting irrelevant comments. Agent_Y is/was looking for help and your post is completely irrelevant
     
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  7. EunosRoadster69

    EunosRoadster69
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    Oh sorry i wasnt thinking when i posted that.
     
  8. Agent_Y

    Agent_Y
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    It's fine, I'm not mad because of that, actually it's kind of funny to see someone think that making Jbeam is fun lol, it's hard work and sometimes annoying or boring but the satisfaction of seeing something you made working in game is worth it
     
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  9. EozCompanyCZ

    EozCompanyCZ
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    Here are some pictures from the Service Manual. Don’t know if it helps but then again it won't hurt anybody either.



    This one is for the 500, but the suspension is almost identical.

     

    Attached Files:

    • 3.jpeg
    • 4.jpeg
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  10. S.Ali.M

    S.Ali.M
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    Yeah I'm agree, I already felt that, especially when I was making burglar alarm mod. That was my first lua code ever in my life! (I already knew python and a little C++, then I figured out python and lua are almost same, so I started writing and sometimes I took a look at other's lua codes)
     
  11. Agent_Y

    Agent_Y
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    Only helps a little bit, shows the camber being 1° positive by default, not sure if it's worth implementing such small camber in game. Would be more useful if it showed the shocks, and for the rear suspension as well, I'm having a hard time finding how long exactly the shocks should be and where should they be attached to the chassis, pretty sure I made mine too long.
     
  12. EozCompanyCZ

    EozCompanyCZ
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    Found this on the internet the top ones are the front ones, and the bottom ones are the rear ones. They are, of course, aftermarket but I can’t imagine them being too different.




    Also this may help

     

    Attached Files:

    • 4.jpg
    • 11350535_10203166730203279_2995390870111120585_n.jpg
    • 11165134_10203082878507039_6802792857609963588_o.jpg
    • 10985444_10203090793304904_1731357079286981281_n.jpg
    • 11247794_10203168805255154_8328312061087966901_n.jpg
    #12 EozCompanyCZ, May 28, 2021
    Last edited: May 28, 2021
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  13. Agent_Y

    Agent_Y
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    I'm not sure if I believe this... I mean the front ones look reasonable, but rear ones look way too long compared to what I've seen on reference images...
    unnamed.jpg
    Unless they are mounted really, REALLY low deep in the suspension arms, in which case my Jbeam is wrong...
     
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  14. EozCompanyCZ

    EozCompanyCZ
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    Here they are:

     

    Attached Files:

    • podvozek1264.png
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  15. Agent_Y

    Agent_Y
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    Oh, this explains everything. The shocks are mounted way up and are longer than the springs. Thanks so much for this, now it all makes sense and now I can make them longer and add more damping to them which they need!
     
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  16. Agent_Y

    Agent_Y
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    Images of the front suspension for reference, maybe they will help:

    Front leaf spring mounting points:
    20210602_204012.jpg

    Leaf spring angle increasing after removing the side mounts (or the whole suspension):
    przednie-zawieszenie-fiat-126p-zwrotnice-resor-busko-zdroj-521551774.jpg

    Good shot of the whole suspension with the rear one too:
    konserwacja5.jpg
     
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  17. EozCompanyCZ

    EozCompanyCZ
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    Also remember that the spring doesn't touch the body in the centre unless fully unloaded.
     
  18. Xupaun

    Xupaun
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    Do those side mounting points move with the suspension? If not, the suspension geometry will behave just like a double wishbone, so you can use a front double wishbone suspension, with a "invisible" lower control arm. The Burnside or Bluebuck IFS may be good for this.
     
  19. Agent_Y

    Agent_Y
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    So the center is not really a mounting point? That's even weirder lol
    --- Post updated ---
    They don't seem to but I don't think it behaves similarly to a double wishbone either, + the Burnside and Bluebuck are both way bigger and heavier so probably recreating that would give some unexpected results
     
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  20. EozCompanyCZ

    EozCompanyCZ
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    I'll try to find a picture
    --- Post updated ---

    Here it is.




    I think I've already send this picture some time back
     

    Attached Files:

    • FrontAxleDetail.jpeg
    • FrontAxleDetailMarked.jpg
    #20 EozCompanyCZ, Jun 2, 2021
    Last edited: Jun 2, 2021
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