Study On Precise Modeling And Fine Pressure Controlling Of Electro-hydraulic Brake System

As driven by the increasingly stringent requirements on safety, environment protection and driver comfort, vehicle technologies have greatly advanced in recent decades. Electric vehicle, in particular, has brought up many technologies or even revolution on the ways as how the vehicles are to be built. Brake system is one of the key subsystems and plays the most important role in vehicle safety and performance. Electric vehicle, including its variation in hybrid, plug-in or range extension, does not provide sufficient or even no vacuum power to assist braking. On the other hand, as driven by electric motors, electric vehicle may be able to recover part of the kinetic energy during braking. Therefore, traditional brake system may not be suitable to meet the new requirements.Traditional automobile braking system cannot meet the needs of future development, the electronic hydraulic brake system not only solved the contradiction of driver control, at the same time their structure are on the large degree of inheritance. Major carmakers such as Toyota, Mercedes implements the large-scale application of related products, of which the electronically controlled brake system (ECB) of Toyota Prius has obtained widespread application in domestic, and comprehensive performance is very good. Therefore, this article will make the ECB system as the research object, combined with 863 research topic on electric hydraulic characteristics of the system.The main line of research is to make the whole system disassembled first and analyzed the work mechanism, including the pedal force simulator, linear electromagnetic valve with both hydraulic analysis and electromagnetic analysis, also the analysis of the liquid capacity of the high pressure accumulator. In order to improve the system performance, we design and build the hardware in loop test bench of electronic hydraulic brake system, formulate the corresponding tests, testing the response of the system and the control parameters of the linear electromagnetic valve, Also including the hydraulic characteristics of high pressure accumulator and PV characteristics of wheel cylinder.This thesis also uses Simscape simulation platform to set up a physical model for the electronic hydraulic brake system and the linear drive model of solenoid valve, We can study the effect of related parameters on the system characteristics, including linear electromagnetic valve closure area, moving iron schedule as well as the influence factor-environmental temperature, the simulation also verifies the validity of the drive mode.Finally, the paper uses Matlab/Simulink to design the pressure tracking control algorithm, the key is to control the system of linear electromagnetic valve and high pressure accumulator, the incremental PID controller is designed, taking the compensation of the solenoid valve control principle. Using Microautobox realized the real-time algorithm of automatic code generation and validation, verify the validity and reliability of the algorithm.