Optimal Lane Change Analysis For Vehicle Platooning Based On Lateral And Longitudinal Control

In the past few decades,with the development of integrated applications and communication technologies applied to transportation systems,vehicle platoon has gradually become a new mode of transportation.It is generally believed that it can improve the energy efficiency and safety of transportation networks.Compared with human driving,platoon driving can shorten the distance between vehicles and allow more vehicles to pass through the same road segment,so the road infrastructure can be better utilized.When researching the vehicle platoon system,the indispensable goal is to add new vehicles through the lane change method to effectively expand the platoon.Safety,comfort,and fuel saving are the goals pursued by vehicles in platoon.In this paper,the extended vehicle platoon is taken as the introduction point,and the optimal lane change problem is studied based on the pursuit of the above goals.The main work is summarized as follows:This paper decouples the research problem in the longitudinal and lateral directions.Based on the error dynamics in the longitudinal direction,a controller for string stability is designed to achieve stable driving in the longitudinal direction.Based on the steering wheel control model in the lateral direction,model predictive control(MPC)is adopted to ensure the smooth completion of the lane change.The influence of lane changing factors on the speed fluctuation of the platoon system is studied,and a fluctuation evaluation index is designed to evaluate the fluctuation caused by lane changing.In two driving scenarios(single vehicle requests to change lanes to join the platoon and vehicle of the platoon requests to join the platoon),the control variable method is used to explore the influence of lane change position and lane change speed on the speed fluctuation of the platoon system.Using the designed algorithm,the optimal lane change speed and lane change distance corresponding to the minimum fluctuation evaluation index are found.Then this work further investigates the relationship between fluctuation evaluation index and fuel consumption,driving comfort,tracking performance.Based on the proposed fluctuation evaluation index,in order to reduce the platoon speed fluctuation caused by lane change and improve the control effect,an MPC controller considering safety distance,following performance,speed recovery ability is designed for the error dynamics.Compared with the controller designed by the general method usingthe fluctuation evaluation index as the measurement standard,the simulation results show the effectiveness of the new design method.In order to coordinate the longitudinal driving trajectory obtained by the optimal lane change factors,the lane change trajectory is planned from the lateral level.The effect of lane change completion time on lane change trajectory is studied,and an objective function that comprehensively considered three factors of driving comfort,fuel consumption,and lane change time is designed.The dynamic penalty function was added to reduce the constraint amount of the objective function.Then the artificial fish swarm algorithm is used to find the optimal lane change trajectory.Finally,the model predictive control is used to track the optimal lane change trajectory.