An advanced flexible realtime tire model and its integration into fraunhofer's driving simulator

In the last two years, Fraunhofer has developed an advanced tire model which is real-time capable. This tire model is designed for ride comfort and durability applications for passenger cars and trucks, as well as for agricultural and construction machines. The model has a flexible belt structure with typically about 150 degrees of freedom and a brush contact formulation. To obtain sufficient computational efficiency and performance for real time, a dedicated numerical implicit time-integration scheme has been developed. Additionally, specific coordinate frames were chosen to efficiently calculate and use the needed Jacobian matrices. Independently from this, Fraunhofer ITWM has developed and installed the new driving simulator RODOS (RObot based Driving and Operation Simulator), which is based on the industrial robot KUKA KR1000. The main application area of this driving simulator are interactive human-in-the-loop simulations with agricultural and construction machines , but also with trucks and passenger cars. For an interactive full-vehicle simulation on the driving simulator, typically at least four tires - together with a real time capable vehicle model - have to be simulated and interactively coupled with the simulator and its human operator. Thus, an administration framework is necessary that organizes and coordinates the simulation of all involved components, as well as the data exchange, in an efficient manner. In this contribution, we describe the development and the implementation of the real time tire model and a coupling strategy for the real time simulation of a full vehicle and four tires. At the end we demonstrate this method in combination with the Fraunhofer driving simulator RODOS.