Vehicle Modeling for High - Dynamic Driving Simulator Applications

When introducing commercial driving simulators a few years ago, the main interest was focused either on operating the vehicle or on the reactions of the driver in traffic and in emergency situations. A comprehensive modeling of the vehicle dynamics was not required for these tasks. However, there are driving simulator applications which make much higher demands on the modeling of the vehicle dynamics. Training simulators for drivers of emergency vehicles or crosscountry trucks have to provide a realistic vehicle dynamics simulation including a detailed tire-ground interaction. This paper presents a generic toolbox of vehicle subsystems that can be used to assemble and simulate in real-time almost any kind of wheeled or tracked vehicle. The toolbox includes all the mechanical or electronic components found in on-road or off-road vehicles. The equations of motion are formulated and solved automatically. The vehicle dynamics is calculated for all six degrees of freedom considering the topography of the terrain, the type of the ground and the aerodynamic forces. Interaction of the vehicle with the terrain is based on an elaborated tire model that allows sliding, skidding or completely loosing the contact to the ground. For illustrating the capabilities of the toolbox, a detailed model of a heavy off-road truck is presented. Several results from the validation procedure and from special driving maneuvers are used to demonstrate the effect of anti-lock braking system or locking differential, when driving near or beyond the physical limits of adhesion.