Research On Lateral Auxiliary Control Strategy Of Intelligent Vehicle

In recent years,with the rise of smart cars,more and more people focus on the assisted driving market.It not only reduces the probability of vehicle traffic accidents effectively,but also optimizes the performance of intelligence and driving performance from the perspective of consumer demand.This dissertation takes intelligent electric vehicles as the research object,a lane keeping assisted control system applicable to both straight and curved roads is established.Finally,the assisted control system is analyzed by theoretical and simulation through a software simulation platform.The main research contents are as follows.First,a wheel-hub motor-driven electric vehicle dynamics model is built,and the motor model and tire model are established according to the whole vehicle parameters and dynamics evaluation indexes,respectively.The accuracy and validity of the vehicle models are verified under different working conditions by simulation.Second,the advantages and disadvantages of the lane departure warning algorithms are compared and analyzed.In this dissertation,different virtual warning boundary lines are designed by combining the driving style of drivers and national standards.And a dynamic TLC warning model based on fuzzy control is established.The danger level of the current vehicle deviating from the lane through the designed fuzzy rules is confirmed,so that it can give the driver a warning sign if changing lane or not.The accuracy of the warning model is verified by using simulation software.Then,in order to improve vehicle driving safety,a lane keeping auxiliary controller based on model predictive control is established by combining the judgment results of the warning system.A two-degree-of-freedom vehicle dynamics model is built as the prediction model,a linear time-varying model prediction control algorithm is derived and a lane keeping auxiliary controller is designed.Constraints are established by considering the physical limitations of the actuator,and the objective function of the auxiliary controller is built,then the objective function is converted into a standard quadratic programming problem.In this dissertation,considering the stability of the vehicle when driving in curves,a lateral stability controller using for compensate for the additional yaw moment is established.Finally,the model and test scenarios are built in Matlab/Simulink and PreScan software respectively.And the simulation is conducted under the national standard of passenger car lane keeping performance requirements and test methods.And the simulation results are analyzed under the scenarios of straight road,constant curvature curve and variable curvature curve.The simulation results show that the lane keeping assisted control system is able to drive the vehicle back to the original lane actively under the condition of invalid warning.