Abstract: The large number of lane departure accidents in high way is due to driver’s inattention and fatigue. A new strategy for the decision of lane departure avoidance, based on dynamic threshold of time to lane crossing(TLC) is presented. The dynamic threshold is calculated by vehicle-lane heading, vehicle speed, road adhesion and reaction time of the implementing agencies and driver in real-time. The decision making of lane departure warning and assistance control is based on the dynamic threshold. A new approach for lane departure avoidance is proposed, which applies additional yaw moment to vehicle to correct lane departure of vehicle by means of differential braking. The desired yaw rate is determined by considering vehicle-lane deviation, vehicle dynamic and limitation of road adhesion. A sliding mode controller(SMC) is designed to control the additional yaw moment. The yaw moment is produced by the distribution of brake forces between the same side brakes with fixed ratio, and lane departure avoidance is carried out by tracking desired yaw response. The proposed lane departure avoidance system(LDAS) is evaluated in Carsim/simulink. Simulation results showed that the proposed method can restrict vehicle into lane range and avoid lane departure accident. A rapid prototyping test platform for LDAS is established, which is composed of CarsimRT/LabviewRT real-time platform, real steering and brake system. The proposed LDAS is validated on the platform. The test result is consistent with the simulation result.

Key words: Differential braking, Lane departure avoidance system, Rapid prototyping test, Sliding mode control