Analysis of the Effect of Inflation Pressure on Vehicle Handling and Stability under Combined Slip Conditions Based on the UniTire Model

The mechanical properties of tires are critical to the driving performance of vehicles. Currently, the tire pressure control system (TPCS) has been applied to achieve different control objectives by adjusting the tire pressure and then changing the mechanical properties of tires. To reveal the influence of inflation pressure variation on vehicle lateral dynamics under combined slip situations, Firstly, the effects of inflation pressure on tire mechanical characteristics under combined slip conditions and the UniTire model considering inflation pressure are introduced. Then, the influence of inflation pressure variation on vehicle handling and stability under both pure and combined situations is investigated by means of an analytical method as well as a handling diagram and phase plane. The results show that the anisotropy of the tire slip stiffness, which can be adjusted by the inflation pressure and vertical load, is the key factor affecting the resultant force direction and the tire force under combined slip conditions. In addition, the influence caused by the inflation pressure variation significantly changes the steering characteristics and the stability of vehicles, as verified by simulations with a 14 degrees-of-freedom (DoF) vehicle model.