Piecewise Affine Tire Model–Based NFTSM Control for Lateral Stability of Four‐Wheel Steering Vehicles

ABSTRACT This work presents a novel lateral stability control strategy for four‐wheel steering vehicle (FSV) under special driving conditions with tire nonlinear cornering characteristics identified in the piecewise affine (PWA) form. The design of the proposed control strategy consists of three steps. The lateral dynamics model of FSV is firstly established in which the tire nonlinear cornering characteristics are identified in the PWA form. The PWA identification model can not only accurately reflect the nonlinear relationship between the tire lateral forces and their influencing factors, but also facilitate subsequent control strategy design. Then, based on the system dynamics model, the nonsingular fast terminal sliding mode control algorithm is adopted to both design the active front steering control strategy which takes the yaw rate tracking error as input and the active rear steering control strategy with the goal of eliminating the yaw rate and sideslip angle tracking errors simultaneously. Finally, to evaluate the performance of the proposed control strategy, the MATLAB/Simulink and CarSim co‐simulation work was carried out. The co‐simulation results proved that the proposed control strategy can achieve better vehicle stability performance than the other two comparative control strategies.