BLIJo's Suspension Discussion

Discussion in 'Content Creation' started by Blijo, Jun 12, 2019.

  1. Blijo

    Blijo
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    A daunting task that can make or break a mod in terms of enjoyment, realism and feel,
    For many one of the hardest tasks to get right,
    The black magic with instantanous centres of rotation, spring values, limiters and other weird things.
    The suspension of a vehicle.
    Let's discus suspensions on this thread in a constructive manner.

    I will start with two examples, one being the buggy V2 I'm making and the other is a 2CV chassis I made a while back.

    The 2CV
    Why the 2CV? Well, the 2CV is an unique vehicle, suspension wise.
    It uses a connected suspension system with a leading arm (wheel is in front of suspension mount) in front, and a trailing arm in the rear(Wheel behind the suspension mount). The springs are operated by a push-pull rod. The springs are under the floor in a cylinder in the middle of the car. Said cylinder is then attached to the frame with it's own springs, making the front and rear connected.
    I made this in BeamNG with a set of slidenodes connected to eachother in said manner. A very early video of it:

    It hinges around the tubes in the frame, those connect to the hubs and thus the wheels. This is a very basic leading/trailing axle jbeam.
    Then in the end of the video I lift the car up and play with the 3 nodes in the center of the car. Those are the springs. The outer ones are the front/rear springs and connected to the one in the middle(note, this is not completely realistic but the basic function is the same). The one in the middle is connected to the chassis.

    You can also see the car jacking up when I brake, this is because it has negative anti dive: the CoG is below the roll(yaw) centre of the suspension. You can do the same with anti squat(acceleration) and even with anti-roll.

    If this car would have a body, the CoG will go up and decrease or reverse this effect, depending on how much it changes. I could also move the suspension axis points further to the centre(making the arms longer) or lower the car a bit to change the roll centre of the car.

    BLIJo's buggy V2(everything is WIP)
    So I'm making a new version of my buggy and let me show some things of the suspension:
    It is a pullrod actuated double wishbone suspension, front and rear work the same.
    upload_2019-6-12_12-11-44.png
    On the left you see the hub/upright, the wheel is attached to this.
    In dark blue you see the two wishbones.
    In purple/pink you can see the pullrod which is connected to the upper wishbone. I did this because I didn't want bump steer, the rear one is connected to the upright.
    The tierod is red and at the same height as the lower wishbone because that's easy for me.
    In lighter blue, you see the rockers. They are angled a bit because that worked a bit better in this config.
    The damping is done with two dampers that run from the inner nodes of the rockers to the chassis. This damps roll and heave(vertical motion).
    The black beam between the two rockers on the pullrod ends is the heave spring. This only stiffens up vertical motion:
    screenshot_2019-06-12_11-34-21.png
    Pretty bad body roll eh?

    Now with basic ARB's and same-ish cornering:
    screenshot_2019-06-12_12-41-50.png
    It needs to be stiffened up a bit but it shows some effect already :)


    Please share your interesting suspension designs, struggles and questions here :)
     
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  2. MrCin

    MrCin
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    When I looked at the title I thought it was a map
    :p
     
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  3. Blijo

    Blijo
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    My bad, changed it :p
     
  4. Nicelittle

    Nicelittle
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    Iv'e got a question, how do you advoid (forgot how to spell that) VY node errors? I can never get the hubs right so the wheels show. Just want a tip on constructing jbeam hubs.
     
  5. Blijo

    Blijo
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    That means that your hub structures are not 3D enough. you can't bind a 3D mesh to a 2D plane.
     
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  6. Blijo

    Blijo
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    Some progress on the "2CV" chassis(no name yet).
    I think it's very smooth right now
    Cornering is also the same as the 2CV, with a lot of body roll:
    screenshot_2019-06-26_15-36-52.png
     
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  7. Nicelittle

    Nicelittle
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    I like how it works, one the design brief for the original was that it had to go through a field with a box of eggs without breaking a single one. Like the 50’s “baby corvette” looks as well.
     
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