Robust Virtual Sensors and Controller Design to Improve Vehicle Stability Enhancement in the Critical Situations

In this paper, tires longitudinal forces, vehicle side slip angle and velocity are identified and estimated using sliding modes (SM) observers. Longitudinal forces are identified using high order SM observers, which permit, in our case, to identify these forces with a high precision and without filtration. In the estimation of the vehicle side slip angle and vehicle velocity, a SM observer based on the super twisting algorithm is proposed. Validations with the simulator VE-DYNA pointed out the good performance and the robustness of the proposed observers. After validating these observers, controller design for the braking is accomplished using a reduced state space model representing the movement of the vehicle centre of gravity in the (X, Y) plane. Driver's reactions are taken into account. The performance of the closed loop system is carried out by means of simulation tests.