Real Time 7 DOF Vehicle Dynamics Model and its Experimental Verification

The paper presents a model derived for real time simulation. It has been applied in low-cost PC-based autoPW driving simulator built at the University of Technology, Faculty of Transportation, Poland. The following assumptions have been done: even, horizontal road surface, no vertical, pitch and roll vibrations of the body as well unsprung masses. The normal reactions of the road are described in quasi-static way. Compliances of steering system as well as description of six aerodynamic drag components are taken into account. The tire model is based on HSRI-UMTRI model with addition of aligning moment description. The model was experimentally verified. Both experimental and simulation tests were based on ISO standards and recommendations: straight line braking (ISO 6597), open-loop response test with one period of sinusoidal input on the steering wheel (ISO TR 8725), steady state circular test (ISO 4138), open-loop response with ramp input on the steering wheel (ISO 7401), severe double lane-change maneuver (ISO TR 3888). Verification was performed for three types of vehicle: small (∼1000 kg) and medium size car (∼1500 kg) as well as for truck (∼11500 kg). Results show good correspondence between simulation and experiment.