In vehicle dynamics, a tire model is a crucial component used in multi-body simulations to replicate tire behavior accurately. These models range from empirical to physically based, with varying levels of complexity and accuracy.
Empirical models like Hans B. Pacejka’s Magic Formula are widely used, while physically based models include brush models and more intricate ones like RMOD-K and FTire. The classification of tire models can be based on their purpose, such as driving dynamics or comfort. Notable models include the Brush model, Hohenheim tire model, Pacejka Magic Formula Tire, TameTire, TMeasy, and the Stretched String tire model.
The selection of a tire model depends on the simulation domain. Mathematical and empirical models treat the tire and rim as a single rigid body, with examples like the Fiala model and Pacejka Magic Formula differing in expressing nonlinear behavior. Rigid ring tire models like MF-SWIFT characterize the wheel as a rigid rim connected to a rigid ring with elastic elements, observing fundamental modes of a pneumatic tire. Flexible ring models like FTire provide detailed tire-road contact surfaces, suitable for rough roads and comfort studies.
Tire modeling is essential for various applications:
- Vehicle Dynamics: Simulations on smooth roads to analyze steering, braking, and throttle responses.
- Vehicle Ride Comfort: Assessing occupant comfort on non-smooth roads.
- Vehicle Durability: Studying peak loads on rough roads for durability analysis.
- Vehicle on Soft-Soil: Evaluating vehicle performance on soft-soil terrains.
Different tire models cater to specific applications:
- Altair Fiala: Enhanced Fiala model for vehicle dynamics.
- CDTIRE & FTIRE: Flexible ring models suitable for dynamics, ride comfort, and durability.
- MF-Tyre & MF-SWIFT: Pacejka Magic Formula-based models for vehicle dynamics.
- PM Flex Tire: A finite element model for vehicle dynamics.
Understanding vehicle dynamics and tire models is crucial for motion control and performance evaluation. These models help in designing controllers by considering parameters like vehicle yaw rate, sideslip angle, stiffness factors, and displacement of the center of gravity. Tire dynamic modeling involves simulating the moment of inertia of the wheel and analyzing factors like friction coefficients for comprehensive vehicle performance assessment.
This overview highlights the significance of tire modeling in vehicle simulations across different domains and underscores the importance of selecting appropriate models based on specific application requirements.
Citations:
[1] https://en.wikipedia.org/wiki/Tire_model
In vehicle dynamics, a tire model is a type of multibody simulation used to simulate the behavior of tires. In current vehicle simulator models, the tire model is the weakest and most difficult part to simulate.
Tire models can be classified on their accuracy and complexity, in a spectrum that goes from more simple empirical models to more complex physical models that are theoretically grounded. Empirical models include Hans B. Pacejka's Magic Formula, while physically based models include brush models (although they are still quite simplified), and more complex and detailed physical models include RMOD-K, FTire and Hankook. Theoretically-based models can be in turn classified from more approximative to more complex ones, going for example from the solid model, to the rigid ring model, to the flexural (elastic) ring model (like the Fiala model), and the most complex ones based on finite element methods.
Brush models were very popular in the 1960s and '70s, after which Pacejka's models became widespread for many applications.