A Method for Overcoming Limitations of Tire Models for Vehicle Level Virtual Testing 2006-01-0499
The intention of this work is to illustrate a method used to overcome limitations of tire models developed during an evaluation study of an Empirical Dynamic™ (ED) damper model. A quarter vehicle test system was built to support the evaluation, and a model of the test system was also developed in ADAMS™. In the model, the damper was represented by a polynomial spline function and by an ED model separately. Vehicle level comparisons between the physical measurements and the model predictions were conducted. The actuator displacement signal from the physical test was used to drive the virtual test system. Spindle acceleration, spindle force, and other signals were collected for comparison.
The tire model was identified as a significant source of error and as a result, the direct vehicle level correlation study did not illustrate any advantage of the ED damper model over a spline damper model.
Subsequently the Remote Parameter Control™ (RPC®) process was used to reproduce lab measured spindle acceleration and body to wheel displacement signals and thus to minimize the influence of the tire model. A fair comparison base was established for vehicle signals above the tire.
After RPC™ iterations, a correlation study was conducted on shock tower load and acceleration signals. It was found that the ED damper is better than the spline damper in high load (velocity) conditions. For low damper force conditions, the model with an ED damper predicts similar results as compared to the model with a spline damper. This is understandable since for conditions of low damper force, the damper exhibits a more linear behavior. In this case, both the spline damper model and the ED damper model were adequate.