Dynamic Tyre Models in Adaptive Slip Control

When designing an automatic brake control system for a car it is important to have a mathematical model of the vehicle to base the design upon. Since careful modeling of the entire car would encompass far too many variables, the most care is usually taken to the wheels and the tyres, as those parts contain most of the dynamics influential to the process. During braking the tyres deform because of the forces between road and tyres. Because of this deformation the braking force from the brake discs is not immediately transmitted to road surface, resulting in a delay of the decelerating force. Tire models mainly aims at describing the friction force between tyre and road surface, and most does this with a function where the friction force is mapped as a static function of the relative velocity between vehicle and tyre. Such a static model considers the tyre to be so sti that it does not deform at all during braking, and does not take deformation into account when calculating the friction force. In this report it is investigated how influential the dynamics from the tire deformation are. By using measurement data from a real car a model for the dynamics is made. This model is made so that it can easily be added to already existing models of tyre and car. Then by the use of this model a controller is designed which takes the tire dynamics into account. It is implemented in simulink and compared to another controller that has been designed based on the non-dynamic tyre model