Research On Response Characteristics And Control Of Automatic Driving Brake-by-Wire System

Hydraulic brake-by-wire system is the development trend of vehicle braking system with rapid pressure construction,accurate pressure control and high system reliability.Research on response characteristics and control of automatic driving brake-by-wire system is of great significance to improve the safety performance of autonomous driving vehicles.This paper focuses on the response characteristics and control of automatic driving brake-by-wire system,and studies the simulation modeling,control strategy,response characteristics and stability control when the system fails.The specific research contents are as follows:(1)The overall architecture of the brake-by-wire dynamic simulation platform for the automatic driving brake-by-wire system is proposed,and the mathematical model including permanent magnet synchronous motor,transmission mechanism,brake master cylinder,solenoid valve,and brake wheel cylinder is established.Subsequently,the simulation model of the brake-by-wire system is built using AMESim software.At the same time,for the purpose of vehicle simulation analysis,the vehicle model is established in Car Sim software.It lays a foundation for the research of control strategy,the analysis of response characteristics and the control of vehicle stability.(2)The overall architecture of the brake-by-wire control strategy is proposed for the brake-by-wire system,and the corresponding controller is designed in MATLAB/Simulink.The permanent magnet synchronous motor adopts three closed-loop control,the solenoid valve adopts PID control,and the open-loop hydraulic response of the system is simulated by AMESim and MATLAB/Simulink.The simulation results show that the system can meet the requirements of "rapid pressure building and accurate pressure control",and verify the effectiveness of the system simulation model and control strategy.(3)The influence of multiple groups of structural and functional parameters of permanent magnet synchronous motor,solenoid valve,brake master cylinder,brake wheel cylinder,and brake pipeline on the response characteristics of the automatic driving brake-by-wire system is studied through simulation analysis.At the same time,the response characteristics of the brake-by-wire system are optimized by using the orthogonal experimental optimization method.After the optimization,the pressure response speed and pressure control accuracy of the system are further improved.(4)The vehicle stability control strategy based on model predictive control algorithm is proposed to address the potential brake failure of autonomous vehicles during driving.The vehicle stability controller and the ABS controller are designed,and the simulation is carried out by combining Car Sim,AMESim and MATLAB/Simulink.The simulation results show that the braking stability of the vehicle is improved under the braking failure condition,which verifies the effectiveness of the stability control strategy designed.