Tyre and Vehicle dynamics by Hans B. Pacejka

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PlatinumZealot
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Joined: 12 Jun 2008, 03:45

Tyre and Vehicle dynamics by Hans B. Pacejka

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What do you guys think about this book? Anyone ever read it?

What has the book enabled you to do after reading it?

:-k
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Tim.Wright
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Joined: 13 Feb 2009, 06:29

Re: Tyre and Vehicle dynamics by Hans B. Pacejka

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I have read the first few chapters and can say its highly technical, very mathmatical. I'm not sure what your background is, but you will need a good mathematical base to get anything from this book.

One interesting thing is that he uses energy methods instead of classical mechanics to form the dynamics equiations. I don't understand why, and for me I've struggled to follow some parts.

I can say that I also found a new appreciation for the Pacejka model after reading what I have in that book. Put aside the fact that the Pacejka formulas are a purely emperical model you will see in the book he derives lateral force curves using a physical brush model and explains how the pacejka formulas represent this in an empirical way. There is also Matlab code in the book for making tread simulations from the formulas in the book.

The Pacejka model often gets a bad wrap, especially in motorsport because its emperical and does not contain a thermal model. Add to that the fact that many Pacejka models are either badly created or badly modified to fit simulation data. But for me, its still the best and most accessable "middle ground" between a linear bicycle model and something more in depth like Rmodk etc.

Anyway, just my 2 cents. I stil have a lot of it to read, just not the time. Its worth a buy if you are working in the industry, otherwise its just a bucketload of maths. If you want something simpler, there are decent tyre explanations in Dixon or Milliken

Tim
Not the engineer at Force India

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PlatinumZealot
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Re: Tyre and Vehicle dynamics by Hans B. Pacejka

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Thanks.. I haven't started reading it yet only glanced over it. I was surprised that he jumped into mathematical formulas from the word go.
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munks
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Joined: 20 May 2011, 20:54

Re: Tyre and Vehicle dynamics by Hans B. Pacejka

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I can agree with most of Tim's post. And while we could expound about the book's (and the Pacejka model's) significant shortcomings, I think there are some specific applications that you're unlikely to find covered anywhere else - like shimmy and the effects of going over ruts and so forth.

But if you want to learn about modern motorsports, where the keys are in the compounding and the management of the tyre temperatures and degradation, I don't really think this book will help you much.

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PlatinumZealot
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Re: Tyre and Vehicle dynamics by Hans B. Pacejka

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I more in it for suspension design, not tuning a particular car for the track.. just mostly theory than practical for now.
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munks
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Joined: 20 May 2011, 20:54

Re: Tyre and Vehicle dynamics by Hans B. Pacejka

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Re-reading my post, I'm a little too dismissive. Pacejka certainly does cover the tire modes and responses and their relationships with the vehicle, and it's very useful for that theory.

Jersey Tom
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Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: Tyre and Vehicle dynamics by Hans B. Pacejka

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Good reference for professionals involved in tire/vehicle modeling.

For those who give the Pac model $*** because it doesn't have a thermal model - "Haterz gon' hate" is what I say.

Thermal model is the least of your concerns for probably 95%+ of applications including pro motorsport. Be more concerned about getting junk test data or "basic" model parameters.

And even then, for times I wanted to start capturing some heat effects I could still do it with a Pac model even if it isn't explicitly defined.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

cheapracer
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Joined: 17 Apr 2012, 15:20

Re: Tyre and Vehicle dynamics by Hans B. Pacejka

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Tyres are made from rubber, that's about it from me but I'm going to steal a friend's post on the subject, Greg Locock is a leading suspension designer/engineer with Ford working heavily with tyre companies and well known/respected in Automotive Engineering circles ...


Here's another tire model http://www.cosin.eu/prod_FTire - The developer is a very helpful guy.

Pacejka is a curve fit, nothing more. The tire model I usually use takes the raw Fz/Fy/camber/steer data from the Flattrac and just tidies it up onto a regular grid, rather than trying to force it to fit a Pacejka equation. This is faster, and possibly more accurate. It also results in big files.

You can predict the effect of small changes to tire pressure and dimensions fairly well, by considering what happens to the sidewall, and hence the stiffness at the contact patch.

The manufacturers (or at least Goodyear and Michelin) have very good non linear finite element models of tires. They are enormous. But i do not know if they can be used to predict wear, or ultimate grip.

Incidentally that brush type model has the great advantage that it does some things that seem intuitively right, and the great disadvantage that in some circumstances it is wrong. I don't know the details.

http://tel.archives-ouvertes.fr/docs/00 ... Kiebre.pdf may also be of interest

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