This mathematical study provides the response of a vehicle at a constant speed and subject to a sudden pull of the steering wheel (angle or torque step). It also enables the influence of the principal vehicle construction parameters to be studied. A particular combination of the equations will enable the vehicle response to be expressed as a combination of 3 basic movements: roll, yaw-sideslip and steering.

Examining the corresponding simplified equations will lead to a physical interpretation of these movements in terms of inertia damping and stiffness.

Finally, we are studying, with the complete model, the effect of combining these different movements using modes, only two of which form the main part of the response. It is therefore relatively easy to forecast, at least qualitywise, the influence of the principal parameters.