Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 01 Sept 2009

Structure and Parameterization of MF-Swift, a Magic Formula-based Rigid Ring Tire Model3

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Page Range: 142 – 164
DOI: 10.2346/1.3138768
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Abstract

Vehicle dynamic simulations require accurate, fast, reliable, and easy-to-parameterize tire models. For this purpose, TNO developed MF-Swift in close cooperation with the technical universities of Delft and Eindhoven. MF-Swift is based on the well-known magic formula model of Pacejka but extending to higher frequencies (60–100 Hz), shorter wavelengths (>0.2 m), and rolling over obstacles by adding a rigid ring and obstacle enveloping model. During the development of MF-Swift, great emphasis was given to experimental validation using dedicated laboratory experiments. With increasing use of MF-Swift in the automotive industry, easy and reliable parameterization has become more important. Therefore, recent efforts have focused on improving the parameter identification process so that it can be conducted with little user interaction and with measurements obtained from industry common test facilities. This paper will discuss the theory behind the improved MF-Swift parameter identification process.

Keywords: tire model; magic formula; rigid ring model; tire dynamics; parameter identification; MF-Swift
Copyright: The Tire Society
FIG. 1.
FIG. 1.

Schematic view of the MF-Swift model.

FIG. 2.
FIG. 2.

Lateral force response to a step in side slip angle for three slip levels at a constant vertical load of 4000 N, clearly showing a quicker response for larger slip angles.

FIG. 3.
FIG. 3.

Calculated eigenfrequencies of a car tire [9].

FIG. 4.
FIG. 4.

Parameter identification process consisting of unique but depending identification steps.

FIG. 5.
FIG. 5.

Measurement (markers) and magic formula fit (continuous lines).

FIG. 6.
FIG. 6.

Effective road surface.

FIG. 7.
FIG. 7.

PSD of the effective height w and plane angle β for a triangular bump for different velocities and vertical loads.

FIG. 8.
FIG. 8.

Enveloping model and null point generation.

FIG. 9.
FIG. 9.

Measured and simulated vertical force response to nine different cleat impacts.

FIG. 10.
FIG. 10.

Measured and simulated longitudinal force response to nine different cleat impacts.

FIG. 11.
FIG. 11.

The various stiffness in the tire model [9].

FIG. 12.
FIG. 12.

MF-Tool parameter identification software.

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