Abstract
Keywords:
Chassis – Tires Interaction - Simulation
Abstract:
The recitation deals with the possibilities of expanding CarSim full vehicle simulation by predicting tire temperatures during vehicle operation and use them for the adjustment of temperature related tire model properties. For this purpose integration of tire specific temperature characteristics in simulation algorithms is provided. The first part fundamentally describes methods for modelling the tire-vehicle environment- interface regarding tire temperature as integral indicators for stress, damage, reliability and performance of vehicle tires by means of statistical engineering (Design of Experiments / “DoE”) and rig-, respectively vehicle testing. Further the methodology for the assessment of tire specific temperature characteristics is explained; thereby the dynamic tire temperatures are described via mathematical formulae for parametrizing of simplified empirical models.
The second part engages with the tire data acquisition using wireless data transmission technology (Bluetooth transmission device) that enables data transfer out of the tire structure to the storage and evaluation unit in the vehicle or at the test rig. At this the interactions between vehicle and tire, as well as the respective interactions between tire, vehicle and environment are considered as the fundament for assessing temperature characteristics and the tire specific parameter sensitivities. This is a possibility to predict tire temperatures under various conditions of operation mathematically, depending on minimal testing work and is the base for modelling tire temperature characteristics. Especially the contributions of tire temperature to specific tire properties like e.g. stiffness, friction, aligning moment, camber thrust, tire spring rate, damping rate and their impacts on vehicle dynamics behaviour are mentioned.
The third section engages with the integration of the tire temperature characteristics into CarSim full vehicle simulation and corresponding tire simulation tools (e.g. MFTire).The virtual determination of dynamic tire temperatures by implementation of empirical tire temperature formulae into CarSim full vehicle simulation algorithms by means of linking Matlab/Simulink subroutines is shown. The approach of a closed loop process using these calculated temperatures by returning to the input data sets of tire characteristics for the purpose of adjusting temperature related tire properties and the corresponding changes in vehicle performance, as well as tire stress is presented; several simulation run examples with tire temperature integration are included into the presentation.