Strategies And Methods Of Driving Micro-Path Replanning For Autonomous Vehicles In The Process Of Lane-Changing

Lane-changing maneuvers are common and important maneuvers in the driving process of autonomous vehicles.Micro-path planning is a key problem in the research of lane-changing for autonomous vehicles.At present,the research of Lane-changing maneuvers of autonomous vehicles mainly focuses on the situation that there is no interference in the lane-changing process and the vehicles change lanes successfully.There is no further study on the situation that vehicles can’t continue changing lanes or even collide with others.So it is necessary to consider the situation that the autonomous vehicles can’t continue changing lanes normally due to the interference.Considering the interference during the lane changing process,this thesis studies the strategy and method of the driving micro-path replanning of autonomous vehicles during the lane-changing process.Numerical simulation and path simulation are carried out.The security and feasibility of the planning path are verified in the simulation environment.The main contents include the following four aspects:(1)The decision-making process of driving micro-path replanning in lane-changing process.Different replanning scenarios of driving paths are established based on different situations of interference during the process of lane-changing.Then the corresponding decision mechanism of driving micro-path re-planning is determined based on the driving maneuvers of vehicles in different scenarios.(2)The method of lane-changing micro-path replanning in lane-changing process.This thesis puts forward the replanning strategy of lane-changing micro-path based on the process of lane-changing.Based on the safety and the comprehensive benefit function which considers the efficiency and comfort of lane-changing,the re-planning method is improved by adding the constraint condition of vehicle state at the end of lane-changing.On this basis,this thesis uses the numerical simulation of MATLAB software to get the optimal re-planning micro-path,and uses the Carsim software to test the safety and feasibility of the optimal re-planning micro-path.(3)The method of lane-changing return micro-path replanning in lane-changing process.This thesis puts forward the replanning strategy of lane-changing return micro-path based on the process of lane-changing return.Based on the safety and the comprehensive benefit function which considers the efficiency and comfort of return,the method is improved by changing the initial and end state of the vehicle’s return process.On this basis,this thesis uses the numerical simulation of MATLAB software to get the optimal return micro-path,and uses the Carsim software to test the safety and feasibility of the optimal return micro-path.(4)The method of micro-path planning method of collision in lane-changing process.This thesis puts forward the impairment path planning strategy according to the loss reduction driving process of the vehicle under the condition of collision.Based on the minimization of vehicle loss,collision mode and collision angle,the optimal location of vehicle loss reduction is determined.Based on the safety and the comprehensive benefit function which considers the efficiency and comfort of driving,the method is improved by changing the vehicle’s initial and end driving state and the position at the end of the time.On this basis,this thesis uses the numerical simulation of MATLAB software to get the optimal micro-path,and uses the Carsim software to test the safety and feasibility of the optimal micro-path.The results show that the vehicle can reach the designated optimal loss reduction position.