Implementation of an off-road tyre model for real-time dynamic driving simulator

The purpose of this thesis is to develop a tyre model for simulating the off-road driving, suitable to run in real-time on professional dynamic driving simulator. The dynamic phenomenon of tyre-soil interaction is complex; considering the fundamental equations of the “Terramechanics”, the model aims to calculate forces and moments, which are generated by the wheel during the contact with a soft soil, such as sand, loam. The model has been developed in Matlab/Simulink environment, using the co-simulation technique with a commercial 14 DoF vehicle dynamics software. The tyre longitudinal forces (traction/braking) have been modelled with the assumption of considering the tyre as a rigid wheel. This is valid if the tyre deformation is negligible with respect to the terrain deformation and it is the case of sand soil. The tyre lateral forces, in this study, do not consider the so-called “bulldozing effect”. Using the same soil properties and an equivalent vehicle model, the results have been compared to those obtained by a commercial multibody software, capable of running reliable vehicle dynamics simulations on deformable terrains. Once the comparison was satisfactory, the developed tyre model has been implemented on a real-time dynamic driving simulator and it gives the feeling of a realistic off-road driving. In conclusion, real-time simulation results have been successfully compared with offline simulation results.