AVL has developed a real time simulation model called VSM (Vehicle Simulation Model) in order to simulate the drivetrain and the vehicle behaviour on dynamic test beds. One of the main tasks is to simulate phenomena and components, which aren’t available on a engine test bed. E.g. jerks of a rear axle, twin jerking with high frequency, electric load or air-condition activation (AC).
VSM model layout was specially designed for real-time application, achieving an optimal trade-off between calculation performance and precision. Model accuracy was implemented to optimally meet the demands of DRIVE.
Physical models were simplified to their effects, as, for example, anti roll bars are not modelled in their geometry but as the effective stabilisation of the vehicle’s body against its rolling motion. Spring and damper characteristics are referred to the motion of the wheels relative to the body, in order to simulate different types of suspension geometry with a universal model.
VSM features a modular design, so that individual models can be replaced easily. The simulation system can be used both ways, as online application on the dynamic test bed and as offline simulation on desktop systems.