Emergency Lane Change Maneuvers Of Articulated Vehicles For Obstacle Avoidance

With the development of science and technology and the continuous improvement of people’s living standards,which provides a broad space for the development of articulated vehicles.But articulated vehicles are prone to accidents,and the accident loss is large,which has become the focus of social attention.At the same time,with the improvement of science and technology,the active obstacle avoidance system for passenger cars has been gradually developed.Therefore,the research of active obstacle avoidance control strategy based on articulated vehicle has social and research value.This paper mainly studies the relevant control strategy of an articulated vehicle in highspeed driving,and finds that there are obstacles in front of it.On the premise of ensuring the stability of the vehicle,this paper uses emergency lane change to avoid collision obstacles,and verifies the strategy.The main research work of this paper includes the following aspects:(1)A three degree of freedom model and a five degree of freedom model of articulated vehicle with active steering are established.The off-line identification of the lateral stiffness of each axle and the roll stiffness of the vehicle in the three degree of freedom model and the five degree of freedom model of articulated vehicle is carried out by using genetic algorithm.By comparing the calculation results of the vehicle model under the same working conditions and by using truck The actual data from SIM simulation verify the effectiveness of the algorithm.Then the map of the stiffness value of the articulated vehicle is drawn when the load changes and the steering wheel angle input changes,and the rollover angle limit of the articulated vehicle is pointed out.(2)A segmented obstacle avoidance trajectory is planned.The characteristics of obstacle avoidance condition are analyzed and the limit of curve is determined.Based on the characteristics of clothoid and Bezier curve,the segmented trajectory is established,and the trajectory parameters are optimized;after completing the trajectory planning,the corresponding safety distance model is established.The safety distance model relies on the rear corner of the car leaving the dangerous area,and compares the system with AEBS system.The conclusion is that the emergency lane change obstacle avoidance can theoretically complete the obstacle avoidance,and play better under high speed and high load,its trigger time is later than AEBS,the required longitudinal distance is shorter,and it has better effect.(3)The trajectory tracking controller of articulated vehicle is established.Based on the three degree of freedom model of articulated vehicle,the kinematic model and trajectory deviation of articulated vehicle are derived,and the trajectory tracking controller is built based on model predictive control.At the same time,the constraint conditions of model predictive control are given by using the five degree of freedom model of articulated vehicle and vehicle performance limitation,and the simulation experiment is carried out based on the co simulation platform of trucksim and Simulink,no load and full load conditions are selected to verify the effectiveness of the trajectory tracking strategy.