Vehicle suspension model development using test track measurements

Abstract

Detailed suspension modeling is a prerequisite for accurate vehicle dynamics simulation. Quarter car models are widely used in the literature, but they are simple and do not capture all dynamic effects. On the other hand, full car models are computationally complex and not available to the designer at initial stage of vehicle development. A test track data based methodology to develop a Laplace domain reduced order suspension model of intermediate complexity between a full car and a quarter car model is presented in this paper. A prototype vehicle is driven on sinusoidal tracks and vertical accelerations of wheel axles and suspension to body attachment points are measured. Using this acceleration data, a transfer function model is fitted to predict the body points accelerations in response to measured wheel–axle accelerations. This model is further extended to incorporate an unsprung mass model and retain suspension properties as free parameters to enable quick parametric studies without repeated field testing. A discussion is given of aspects of the model that match experiments, as well as possible sources of observed mismatch. Finally, two potential applications are given to study the effect of suspension and unsprung mass model properties on body point responses.