Abstract: In order to make full use of differential braking control and active steering control with concurrent consideration of vehicle driving safety and the driving freedom of driver in designing lane departure prevention system, a lane departure prevention strategy with two-stage warning is proposed, utilizing coordinated control of active steering and differential braking. When the vehicle is in low risk, only differential braking control is used to ensure driver's control on steering wheel, and when the vehicle is in high risk, predictive control is adopted to achieve the coordination control of active steering and differential braking systems, so that the vehicle can quickly return back to the center-line of the lane. The time to lane crossing is selected to design the lane departure warning algorithm, with two warning thresholds set according to the response of the steering system of the vehicle respectively for low and high risk. To ensure vehicle stability, model predictive control with appropriate constraints is used to design the differential braking controller and coordinated controller of active steering and differential braking. The results of simulation and hardware-in-the-loop test show that the lane departure prevention control strategy designed based on the coordination of active steering and differential braking gives the driver full driving freedom while ensuring the premise of vehicle driving safety

Key words: active steering, differential braking, time to lane crossing, two-stage warning, model predictive control