An Integrated Lane-changing Trajectory Planning Model For Automated Vehicles

With the rapid development of computer technology and sensing technology,automatic driving technology has attracted more and more attention and is considered to be an important technology to effectively solve environmental pollution,traffic accidents and traffic congestion.More and more Internet enterprises and traditional automobile enterprises are carrying out autonomous vehicle testing,but the frequency of automatic driving accidents shows that the existing technology is not perfect.Among them,vehicle lane-changing technology is one of the key problems of autonomous driving technology,which attracts the wide attention of scholars in related fields such as transportation and automobile.Taking the modeling of vehicle lane-changing behavior under the background of autonomous driving as the research direction,this paper considers the process of vehicle change preparation in the field of automatic driving vehicle change for the first time,and establishes the model of road change preparation and implementation of integrated trajectory planning.According to the change of traffic environment,the static and dynamic integrated lane-changing trajectory planning model is established respectively to study the process of vehicle changing course.In the static integrated lane-changing trajectory planning model,the vehicle lane-changing trajectory is generated by using straight line and five polynomial curves,and the collision avoidance algorithm suitable for vehicle lane-changing is established on the basis of Gipps theory to ensure the safety of vehicle lane-changing,and then the optimal safe lane-changing trajectory is calculated based on the cost function of vehicle comfort and efficiency.Because the static model cannot guarantee the safety of the vehicle in the case of sudden emergency,the applicability in the real traffic environment is limited,so a dynamic integrated lane-changing trajectory planning model is established to enable the vehicle to realize the dynamic response to the change of environmental information.On the basis of static model,the dynamic model considers the change of the position of the vehicle in the process of lane-changing,establishes a new collision avoidance algorithm which is more in line with the actual lane-changing,and introduces the dynamic vehicle change track decision algorithm,determines the security of the trajectory in real time,and generates the safe decision result,in order to improve the security and adaptabilityThe results show that the integrated lane-changing trajectory planning model of autonomous vehicle can effectively improve the vehicle changing environment,and then improve the success rate and safety of vehicle change channel,in the preparation stage of the road,the vehicle adjusts its own speed and the relative distance between vehicles,and creates a safe lane-changing environment.The integrated trajectory planning method is more suitable for the real traffic environment than the non-integrated planning method,the comfort and efficiency of the integrated trajectory are higher,and more suitable for demanding lane-changing environments.By simulating and analyzing the influence of the changing environment on the process of vehicle changing,it is found that not all changing lanes need to change the preparation stage,when the vehicle changing conditions meet the safety constraints,the vehicle directly performs the road change execution process,there is no change preparation process,in addition,the vehicle speed is always close to the surrounding vehicle speed in the process of changing lanes In the successful lane-changing and change stop scenario of NGSIM data construction,the integrated trajectory planning model can plan the path and return trajectory to meet the comfort,efficiency,and safety,so that the vehicle successfully changed lanes or safely returned to the original lane,waiting for the next opportunity to change lanes.In addition,CarSim simulation results show that the trajectory and speed planned by static and dynamic models can be tracked well,and the changes of vehicle parameters are in line with the reality,so the feasibility and applicability of the integrated lane-changing trajectory planning model are high.