FIRST PRINCIPLES


Refining tyre models for use in racecar simulation – part one BY DANNY NOWLAN


question I am asked over and again is, 'Okay, I have my racecar tyre model, but what do I do to


make it match up to real data?' The real reason I tend to get asked this question is that a great many people in racing are still coming up to speed with what a tyre model is, and how it actually works. Believe it or not,


it’s not voodoo magic, it’s just a matter of knowing what’s going on under the bonnet, and using a bit of common sense. In this article we are going to use ChassisSim to refine a bit of simulated data. I’m not doing this for a sales plug, it’s just what I’m most familiar with. Don’t worry if you use other simulation


It's not Voodoo A


packages as the techniques are equally applicable. When refining our simulated tyre model, this is our order of attack:


• Match the lateral acceleration and corner speeds


• Match the steering trace and hence the handling characteristics


• Match the longitudinal acceleration


This approach has served


me very well in achieving great correlation in countless formula. Before we begin, though, we


need to do a bit of preliminary maths so we can understand what we are doing. To refresh the reader’s memory, let me present the ChassisSim v3 approximation again (see equation 1). When refining the racecar


September 2011 • www.racecar-engineering.com 77


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