Parameter Identification for Combined Slip Tire Models using Vehicle Measurement System 2018-01-1339
It is imperative to have accurate tire models when trying to control the trajectory of a vehicle. With the emergence of autonomous vehicles it is more important than ever before to have accurate models that represent exactly how the vehicle will operate in any situation. Many different types of tire models have been developed and validated, including physics based models such as brush models, black box models, finite element based models, and empirical models driven by data such as the magic formula model. The latter is widely acknowledged to be one of the most accurate tire models available however collecting data for this model is not an easy task. Collecting data is often accomplished through rigorous testing in a dedicated facility. This is a long and expensive procedure that will generally destroy many tires before a comprehensive dataset is acquired. Using a Vehicle Measurement System (VMS), tires can be modeled through on-road data alone. This reduces the time and cost significantly and doesn’t require destroying multiple tires. Previous works regarding this method have used only the basic versions of the magic formula model - pure longitudinal slip and lateral sideslip - however the full model includes combined slip conditions as well. To accurately mimic the tire forces, especially in safety critical situations autonomous vehicles are in frequently, combined slip tire models are necessary. The longitudinal slip, side slip angle, and all the tire forces and moments were measured and calculated using the VMS during normal and extreme driving scenarios. The data was then used to identify the parameters for the 1996 Pacejka model for pure slip and combined slip scenarios.