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Thread: FSAE Tire Test Consortium -- Round 3

  1. #81
    "I saw a lot of hysteresis on raw data graph i.e. for IA=4? tests pass trough SA=0 four times and 2 curves indicates a lot of FY+ and the 2 others indicate approximately 0."

    All of the curves pass through zero four times. That's how the tests are run, watch the test videos. They pass each tire through zero four times in order to get as much data as possible in that area, so they can approximate the cornering stiffness as accurately as possible.

    As for the problems with the Goodyear tire I agree with you that its camber response doesn't seem right. MRA is aware of the problems and have scheduled time to fix them.

    I hope that helps.
    Vince Libertucci
    U of T Racing Alumn
    2004 - 2008

  2. #82
    Hi VinceL,

    Thanks for the details.

    In fact, for the test, I know how they are run... my point was more about FY value of these curves. There is effectively 4 curves that pass through zero but 2 of these curves give a FY value of about 30 lbs for lateral force while the 2 other curves give a lateral force near to zero (which is what is expected). I wonder what caused this difference.

    If MRA is aware of the problem, do you know when we should expect to have some news from them? How do you know the are aware of the problem? Is there any place where the known problems are listed?

    Thanks!
    Luc,
    FSAE Université Laval

  3. #83
    Hi all, I'm developing a vehicle dynamics model of our Formula Student car, using MatLab Simulink (SimMechanics) I would like to incorporate Pacejka's tyre model into this eventually. Does the Tyre Test Consortium data give Pacejka coefficients of the tyres?

    Secondly I have a problem; my university wont fund the cost of the FSAE tyre data until I have a model that I can prove will work with pacejka coefficients. So I wonder if anyone has pacejka data for a somewhat 'random' tyre that they would send me? Just to get a working model with Pajecka coefficients that are roughly the right orders of magnitude...

  4. #84
    Senior Member
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    Jonny_B, I believe you can find Pacejeka coeffiecients of a tire just using Google. In fact I believe a set of coefs. are given in RCVD. And yes Pacejka coeffiecents are given from the tires, although I personally prefer the MRA Non-dimensional model and if you are writing your own code, I'd use that.

    On another note, is there anyone else that would like to see a "closed" forum where schools that have bought the data can discuss it and post plots and figures? Maybe that is something that can be organized in collaboration betweend FSAE.com and Dr. Kasprzak/Dr. Milliken? I mean on this forum we are able to dicuss nearly any aspect of the cars. I don't know about you, but I've learnt quite a lot from these forums, why shouldn't we be able to learn about tires as well?
    KTH Racing '03-'08
    Dartmouth Formula Racing '07

  5. #85
    Yes, a closed forum would be great. It would be easier to discuss about data if we can post graph.
    Luc,
    FSAE Université Laval

  6. #86
    Hi all,

    I owe several people e-mail replies. I've been traveling and am swamped with paid work right now, but I hope to catch-up on my FSAE TTC correspondence in the next week or two.
    Dr. Edward M. Kasprzak
    President: EMK Vehicle Dynamics, LLC
    Associate: Milliken Research Associates, Inc.
    Co-Director: FSAE Tire Test Consortium
    Lecturer: SAE Industrial Lecture Program
    FSAE Design Judge

  7. #87
    OK Can someone tell me about this non-dimensional tire model that is included with tthe tyre data? Is it a 'combined' model such that lateral slip angle will also affect the longitudinal force? I need to write the tire model into MatLab code for my dynamics model - is there any problem with doing this? Also are we provided with mathematical code for the easy generation of tire curves?

    We will be purchasing this soon if it does meet our requirements.

    Thanks,

    Jon.

  8. #88
    Senior Member
    Join Date
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    Jon, a MATLAB script that uses normal load, inclination angle, slip angle, slip ratio as input and gives you lateral and longitudinal force is included with the data. The non-dimensional model is described in RCVD.

    The same script can be used to create tire curves as well.
    KTH Racing '03-'08
    Dartmouth Formula Racing '07

  9. #89
    OK thants good. Finally, how long will it take for the disc to be posted to us (need it ASAP), and are we directly given all of the coefficients that we need to construct tire curves for each of the tested tires?

    Thanks,
    Jon.

  10. #90
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    Join Date
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    All the coefficients are in *.mat files called by the script. Each tire has its own *.mat file.
    KTH Racing '03-'08
    Dartmouth Formula Racing '07

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