Bosch LapSim Tire model

[henningo]

thread108-265917

Hi,

cibachrome mentioned in the referenced thread a method to generate tire models for Bosch LapSim from test data. Anyone know more?

Thanks!
Henning

 

[dfoxengr]

looks like he was probably referring to a pacejka model which can be derived from empirical test data from a flat track machine or some road testing. the model is probably slip angle/lat force, camber/lat force, etc

 

[cibachrome]

The LapSim tire model is an elegant 4 term Pacejka-Lite function. Coefficients can easily be fit using Matlab. I also have produced MZ and MX funtions for the same equation that are very useful in other simulations as well as tire specification requirements documents. MZ and MX are not utilized in LapSim. You can produce the coefficients from machine test processes as well as road wheel transducer results.

Is it allowed to post code here? Don't want to break any protocols. I've given it to the FSAE teams (via the TTC Forum) so they can fit the Calspan/TIRF FSAE tire data for simple (yet elegant) vehicle dynamics modeling suitable for choosing tire constructions and pressure for their vehicle(s). Its actually very simple to do. I also have posted there a Matlab GUI with Sliders to show how each parameter modifies the shape of the tire function (initial slope, peak value, peak location and function limit value. For most of the thousands of tires I've tested (including race slicks), its does a VERY good job. If you also have camber information, a camber sensitivity value suitable for LapSim is produced. I believe you now have to use the purchased version of LapSim in order to actually change tire properties in the model. Just changing the panel values no longer has any effect on the results. In earlier version, changing a tire changed the results.

Again, not sure how I would post code blocks or running GUI scripts, but I could give you the function and the table of contents on how to do it and which optimizer is used. If you have access to the FSAE TTC, its all there. TTC = Tire Test Consortium. The Milliken site has a link to it.

 

[GregLocock]

I'd be very interested in that code. Best way is to zip it up and then upload the zip using the link at the bottom of the submit post textbox.



Cheers

Greg Locock


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[dfoxengr]

please do post your matlab gui, and other code.

 

[cibachrome]

Lapsim zip file. The GUI was created with Matlab v7.1 There may be some special text display stuff in there (sorry, its been a while). If so let me know and I can add it in.