Modelling vehicle dynamics for virtual experimentation, road test supporting and dynamic control

Product development in automotive industry is still deeply based on experimentation: test benches and road test facilities are used both for components testing and models validation. Nevertheless a growing role is played by numerical simulation and nowdays by virtual experimentation. The latter is required by the increasing complexity of the systems and cost saving. Moreover new products involve a higher level of integration between mechanics, electronics and computer science, which makes difficult a rapid and low cost prototyping. The design of the vehicle is currently applied to the overall system instead of assembling subsystems separately developed and tested. This approach requires that the same level of integration is achieved on numerical codes and simulators, to be able to operate hardware and software for virtual experimentation in mechatronic systems. This paper briefly describes the experience done since few years, by Fiat Auto and Politecnico di Torino (Dept. Mechanics) in developing methods and codes for vehicle dynamics modeling, also in presence of active devices for driver assistance. Several models have been assessed and validated and look suitable to support simultaneously road testing and chassis design, as well as education and entrainement of specialized teams. Numerical and experimental results are shown to describe the level of approximation achieved in vehicle dynamics prediction. Preferred environments of codes development have been MATLAB and SIMULINK, eventually operated in co-simulation with other products, like ADAMS Car (MDI) and SWIFT-TYRE (TNO). This allows having a lighter code, open for improvements, quite popular and known both for road test technicians and designers. Several applications to product development are already performed and herewith documented, to define the role of the proposed methods and simulators, although the integration of active devices for driver assistance systems is still an open subject in vehicle dynamics know-how.