Research On Multi-mode Adaptive Cruise Control System For Autonomous Vehicles

As an important part of the Advanced Driving Assistant System,the Adaptive Cruise Control(Adaptive Cruise Control)system can effectively reduce the driver's operating intensity and improve the driving safety,comfort and fuel economy of the car.It has attracted extensive attention from domestic and foreign OEMs and research institutions.In view of the single function of the current adaptive cruise system,it cannot adapt well to the complex and changing traffic environment and the insufficient consideration of vehicle comfort and fuel economy in the design of the controller,this paper designed a multi-mode autonomous vehicle Adaptive cruise control system.The main research contents are as follows:First,build a vehicle model based on the Carsim simulation software,and then compare the simulation results with the Carsim vehicle model based on the experimental data collected in the actual car experiment to verify the accuracy and effectiveness of the model.Secondly,in view of the unpredictability of the movement state of the preceding vehicle and the driving intention in a complex traffic environment,this article subdivides the driving conditions of the ACC system into 5 different modes according to the urgency of the vehicle while driving:Cruise mode,acceleration approaching the preceding vehicle mode,deceleration approaching the preceding vehicle mode,emergency following mode and steady state following mode.Then,according to the calculation of the fuzzy controller,the emergency coefficient im in the following process is obtained,and the mode switching is completed.Then,aiming at the defect that the existing ACC system does not fully consider the following performance and comfort in the decision algorithm design,according to different control modes,the corresponding algorithm is adopted to solve the expected self-vehicle acceleration considering safety and comfort,and it acts on The controlled vehicle realizes the function of the vehicle's adaptive cruise control system.Among them,the PID control algorithm is used to solve the expected acceleration under constant speed cruise conditions to track the set cruise speed;for the remaining four tracking modes,the MPC control algorithm is used to solve the expected acceleration.In order to improve the adaptability of the ACC system to the driving environment,this paper proposes a variable weight coefficient method based on fuzzy rules.For five different driving conditions,fuzzy control theory is used to online judge and identify the following weight of the target function Coefficient and comfort weighting coefficient,by setting the appropriate weighting coefficient,to achieve the purpose of focusing on the following performance and comfort under different working conditions.Finally,based on Matlab/Simulink and CarSim simulation software,build a joint simulation platform of ACC system.The effectiveness of the multi-mode ACC system designed in this paper was verified by simulation tests under four typical driving conditions,including front vehicle speed change,front vehicle cut-in,front vehicle cut-out and NEDC-suburban conditions.The simulation results show that the multi-mode ACC system control algorithm designed in this paper has a good control effect and has a good tracking effect in four typical scenarios.