2.1 Tyre Models
Tyres are important components of automobiles; they support the weight of the car and reduce the impact from ground, amongst other things. At the same time, through the interaction between the tyre and the ground, forces and torques which change the car’s motion can be produced. The forces and torques include tractive force, braking force, and aligning moment. The dynamic behavior of tyres is critical to the car’s handling, ride comfort, traction, and braking performance. The accuracy of dynamic performance analysis and the success of the chassis control system design rely heavily on the accuracy of the vehicle dynamics model and the tyre dynamic model.
Modern tyres are complex viscoelastic structures. The relationships between forces, deformation, and motion are highly nonlinear; thus, it is very difficult to establish a precise mathematical model. Since the 1930s many scholars have carried out plenty of research and achieved fruitful results on tyre modeling. In summary, tyre models fall into three categories: theoretical models, empirical models, and semi-empirical models. Before explaining these models in detail, some terminology and concepts are introduced in advance.
2.1.1 Terminology and Concepts
- Tyre axis system and six-component wheel force
The standard tyre axis system defined by the U.S. Society of Automotive Engineers (SAE) is the most commonly used in tyre modeling. Three forces and three moments acting on the tyre by the road ...