Analysis Of Dynamic Response Characteristics And Research On Hardware-in-the-loop Test For The Automobile Electro-hydraulic Braking System

The emergence of driverless cars and new energy vehicles has provided new methods for solving urban traffic congestion and improving environmental pollution.The development of new energy technologies,such as Brake-By-Wire system,has attracted more and more attention.And advantages of high stability are increasingly valued by engineers and people.The Brake-By-Wire system can be divided into two main systems in principle,namely the electro-hydraulic braking system and the electro-mechanical braking system.The electro-hydraulic brake system preserves the structure of the traditional hydraulic brake system,and adds a switching valve and pedal feel simulation sensor.When the electro-hydraulic brake system actively brakes,the motor pump serves as a power source to the brake wheel cylinder.When the brake of the electro-hydraulic braking system fails,the switching valve is powered off to restore the connection between the master cylinder and the brake wheel cylinder.The driver can provide braking force by stepping on the brake pedal to avoid the car from losing stability.For the operating characteristics of the motor pump high pressure accumulator as the power source in the fully decoupled mode of the electro-hydraulic braking system,the dynamic response characteristics of the actuator of the system are the key to the rapid pressure build-up and precise pressure control of the electro-hydraulic braking system.problem.This article focuses on the analysis of " Analysis of Dynamic Response Characteristics and Research on Hardware-In-the-Loop Test for the Automobile Electro-hydraulic Braking System" from the following aspects:1.The establishment of the simulation model of the electro-hydraulic braking system.In order to explore the dynamic response characteristics of the actuator of electro-hydraulic brake system,this paper analyzes the working principle of theactuator,deduces the physical and mathematical model of the actuator,and simulates the actuator of the hydraulic brake system based on Matlab/Simulink software.The model mainly includes high pressure accumulator model,linear intake valve model,normally closed electromagnetic valve model,brake hard pipe model,brake hose model and brake wheel cylinder model.2.Analysis of the response characteristics of the electro-hydraulic brake system.Based on the simulation model of the actuator of the electro-hydraulic brake system,the effect of the change of actuator parameters on the response characteristics of the wheel cylinder pressure booster is analyzed.Since the switching characteristics of the electromagnetic valve directly affect the boosting characteristics of the brake system,the key parameters such as the preload of the solenoid valve of the linear intake valve,the area of the inlet valve port,and the number of turns of the solenoid valve are taken into account.Based on the influence of the braking system,a wheel-cylinder pressure control algorithm for the electro-hydraulic braking system was designed.3.Set up a hydraulic control system simulation platform and perform a joint simulation analysis based on the Carsim vehicle model.In order to study the response characteristics of the electro-hydraulic braking system under the actual operating conditions of the vehicle,an adaptive cruising co-simulation model was built and an acceleration state switching module and a drive motor module were designed.Based on the actuator model of the brake system and the Carsim vehicle model,active boost conditions and typical operating conditions were analyzed.The brake system response under the system’s active boost condition,front and rear car following conditions,and NEDC operating conditions was studied.characteristic.4.Based on NI-cRIO data acquisition system,the hardware-in-loop test bench of the Electro-hydraulic braking system was built,and the wheel-cylinder pressurization characteristic test,solenoid valve response characteristic test and wheel cylinder pressure control algorithm response characteristic test were carried out.Through experiments,the actual boosting characteristics of the braking system are investigated,and the correctness and effectiveness of the effective linear control zone and wheel cylinder pressure control algorithm for the PWM signal of the electromagnetic valve are verified.