Abstract
In several cases analysis of low speed cornering manoeuvre of the vehicle is needed, generally for the development of vehicle dynamical systems. Low speed cornering happens mainly in case of parking. Due to the low velocity static tire models are not appropriate, structural models should be applied. In structural models the elasticity and the damping property is taken into account, and any kind of friction model is applied as well. The behaviour of the wheel can be described with dynamical equations. Actuating external forces and torques on the wheel both the trajectory, the tire forces and the tire deformation is computable as well. Road vehicles are equipped with more and more vehicle dynamical systems to increase the safety of the traffic and to help the driver controlling the car. These systems have influence on the vehicle’s motion state. To interfere into the vehicle’s motion the system has to know how the car will react to the change of the control parameters, just like the steering angle or the acceleration pedal or brake pedal position, i.e. the motion vector of the vehicle. Further more it can be also important in special cases the vehicle’s computer has to know the vehicle’s actual position.
For this a specialised vehicle model is needed. The model tells the system how the vehicle will behave to different input signals, and the current position of the vehicle related to a predefined coordinate system. To develop a mathematical model we need to write up the dynamical differential motion equations of the vehicle, which describe the vehicle’s motion. Each system or analysed problem needs its own specialised model. There are models which can reproduce the total vehicle motion in all the six degrees of freedom. These types of models are used only in vehicle simulator programs which are applied for developing different vehicle dynamical systems. But in several cases it is enough to develop a simplified model which is only able to describe some basic motions of the vehicle. For example for developing a brake system the roll, yaw displacements and rates, vertical and lateral accelerations are ignorable, only the longitudinal accelerations and pitch motion are to be taken into account.
Keywords: Tire model, vehicle model, low speed cornering, vehicle motion simulation, tire deformation