Development of shared steering torque system of electric vehicles in presence of driver behaviour estimation

This paper proposes a new approach to develop a preventive driver assistance system for lane keeping of electric vehicle. It is used to add a steering torque to that of the driver when there is degradation in driver performance (fatigue, drowsiness or inattention). Based on cybernetic model of driver, the driver's behaviour has been estimated by using extended Kalman filter. An optimal linear quadratic regulator (LQR) controller is designed to impose a corrected steering torque on the steering wheel by minimising the cost function that contains all signals related to the electric vehicle and the driver's behaviour. The proposed controller model based on three degrees of freedom has been implemented on an electric vehicle using MATLAB/Simulink environment. The performance of the cooperative operation between the driver and the active steering torque controller is further evaluated by simulation tests.