The Method Of Planning Lane Change Trajectory Based On The Flow Field

Lane change is one of the main driving behaviors, lane changing safety has become the focus of research at home and abroad since there is more accidents of the lane change process, lane changing safety includes vehicle stability and not collide with other vehicles. This article will consider two aspects, get the final vehicle lane changing tracks by the model which is determined according to lane changing security. Finally, a simulation experiments will be given.The research of lane changing security is very common at home and abroad, but mostly based on static security lane changing model to decide such as trigonometric function lane-changing model, the circular arc model, constant migration model, expecting acceleration model, etc. The models which have mentioned are not perfect with defects, such as discontinuous curvature, complicated calculation and poor accuracy, that it is hard to judge security of vehicle constantly. Therefore, this paper proposes a new model of lane changing track which is able to calculate real-time security.Firstly, the vehicle outflow field distribution is calculated by CFD simulation, and then database is built. Then DS evidence theory is used to fuse normalized horizontal and vertical velocity data of vehicle outflow field, and set the vehicle security domain by determining the data field according to the safety of each unit. Secondly, this paper proposes a new five polynomial model of lane changing track, using ant colony algorithm to solve the optimal lane changing trajectory, the objective function is the handling stability of the vehicle, determining vehicle lane changing real-time security uses DS evidence theory fuses weighted vehicle safety domain data and the relative tilt angle with the trajectory of the vehicle according the best lane changing tracks. Finally, an example of completing the lane change that the vehicle speed is 30m/s is proposed to simulate, meanwhile, corresponding countermeasures are given about emergency situations according to analysis of a simulation example.The proposed polynomial lane changing trajectory model is adaptable, and has continuous curvature, simple calculation real-time determination of the vehicle lane changing security through research and analysis, provides a theoretical basis of lane change.