Research On Vehicle Adaptive Cruise Key Control Algorithm

Adaptive Cruise Control(ACC)system has been greatly used in medium and high-grade vehicles to improve the safety of the drivers.As an assisted driving system,it can reduce traffic accidents and the drivers fatigue feeling at the same time.However,the ACC system,which has a single goal of driving safety,is not sufficiently concerned with the user’s driving comfort.Therefore,when it comes to the workshop time distance algorithm designing of the ACC system,this thesis do a lot of work aims to different kinds of target vehicles,and proposes a workshop time distance algorithm based on the front vehicle type and psychological field,which improves drivers comfort and vehicle safety.In the part of ACC system controller designing,this thesis focus on the control accuracy of the controller when there are system errors,and proposes a PID control algorithm based on Kalman and an improved BP neural network to improve the anti-interference ability of the ACC system.The main work in this thesis are as follows:(1)Based on the theory of vehicle dynamics,this thesis analyses and builds up the theoretical model of each component module of the vehicle.Firstly,the longitudinal dynamics model of the driver’s control of the vehicle’s motion is analyzed,according to the different input,it is divided into a driving system and a braking system.Then,this thesis takes the air resistance,driving force,braking force,and rolling resistance received by the vehicle during driving into consideration.The vehicle body model,transmission system model,braking system model and tire model were built,which laid a solid foundation for subsequent simulations.(2)This thesis proposed a brand new workshop time distance algorithm between cars based on the type of front car and psychological field.The existing ACC distance control algorithm mainly considers the safety among vehicles the comfort of the drivers and this thesis do not take the economic status into consideration,and ignores the impact of the difference of the target vehicle at the same time.To this end,this thesis considers the differences of target vehicles,combines the theory of psychological field,and proposes a novel ACC control algorithm which comprehensively considers driving safety and comfort.so that vehicles with ACC system can adjust the vehicle distance according to the type of target vehicle,which improve the safety the vehicles and the comfort of the drivers.(3)This thesis proposes a PID vehicle status control algorithm based on Kalman filtering and improved BP neural network.As we all know,the control algorithm of the existing ACC system mainly considers the control accuracy of the throttle opening and the brake pressure,and the control process is carried out by the ACC vehicles’ controller.However,traditional ACC system ignores the effect of system error on vehicle.Consequently,this thesis considers the anti-interference ability of ACC system,combines the Kalman filtering algorithm,and proposes a novel ACC control algorithm which comprehensively considers Anti-interference ability and control accuracy.The new control algorithm uses Kalman to reduce the measurement noise of the ACC system and cut back the amount of interference,meanwhile,uses improved BP neural network can be used to map non-linear functions and the self-learning method,the optimal parameters of PID vehicle state controller are obtained.As this ACC system not only satisfies the control accuracy,but also improves the anti-interference ability,ensuring the safety of the vehicle and the comfort of the driver.(4)The simulation proves that the proposed algorithm can be effective and reliable.In order to verify the control effect of the proposed algorithm in this thesis,which combines workshop time distance algorithm based on the front vehicle type and the psychological field theory and the PID vehicle status control algorithm based on Kalman filtering and improved BP neural network in the ACC system,this thesis builds an ACC system simulation platform using co-simulation method of Carsim and Simulink.This thesis choses operating conditions of cruise,cut-in,follow-in,quick brake,low-speed start-stop,and cut-out to simulate the ACC system which uses the new designed algorithm,and compares with ACC vehicles those use other control algorithms to verify the control algorithm that proposed in this thesis,which verified the effectiveness and reliability of the algorithm.The results showed that under specific simulation conditions,the ACC system using the control algorithm proposed in this thesis has effectively improved the deficiencies of the traditional ACC system,which not only ensures the safety of the vehicle but also improves the comfort of the driver,thus meeting the design requirements of this thesis.