Investigations of the process of road matching on powertrain test rigs

This paper will present investigations and a methodology for the matching between the vehicle behavior on the road and on the powertrain test rig. The focus lies on the mathematical tire model of Pacejka [1], which is used on the powertrain test rig to describe the force between the tires and the road. If the model parameters of the tire manufacturer are not available, they are determined in an iterative process. For this purpose, the tire parameters are varied in a driving maneuver until the deviation from the road data is reduced to a minimum. In [2], a new methodology has been introduced. This new methodology uses an empirical black box model to describe the difference of the measured signals of the driving maneuvers between the test rig and the road. The inputs of the model are the Pacejka parameters, so that the optimal parameters can be determined with a numerical optimization. This methodology reduces the duration and the effort to calibrate the test rig. In some application scenarios it can be difficult to compute the Pacejka parameter in a single test because the influence of the parameters on the behavior of the transferred force varies with the level of tire slip. Therefore, it is necessary to split the parameter identification based on the Design of Experiment and black box modeling in two different tests with an operating point with a high tire slip level and an operating point with a low tire slip level. In the first test, the slope of the low slip range and in the second test the required Pacejka parameters will be determined.