Robust control with parameter uncertainties for vehicle chassis stability in critical situations

This paper describes a state feed-back tracking controller with parameter uncertainties for vehicle dynamics with a four-wheel active steering system as well as an active suspension system. The objectives of the proposed controller are to improve the vehicle behavior by forcing the lateral dynamics and the load transfer ratio to track the desired vehicle behavior in critical situations. The Takagi-Sugeno (TS) representation has been used in order to take into account the non-linearity of the cornering forces. Moreover, the variation of the tire cornering stiffness has been considered through parameter uncertainties. Based on the obtained uncertain fuzzy model, the controller design has been formulated in terms of Linear Matrix Inequality (LMI) constraints. The proposed techniques have been evaluated through an obstacle avoidance test conducted in MATLAB/Simulink®.