Research On A Vehicle Brake By Wire System

In the current vehicle intelligence and autonomous driving and other research boom,the automotive components are gradually toward the highly integrated and electronic development,the vehicle braking system is also gradually toward the brake-by-wire system development.To meet the vehicle active safety,such as automatic driving technology development and requirements to improve the performance of vehicle dynamics,this paper proposes a based on direct drive hydraulic source and three high-speed on-off valve line control system scheme of vehicle,and through the system modeling,simulation calculation and the principle of sample test method was carried out by related research,mainly finished the following work:(1)system scheme design and analysis.Combined with the conventional braking system,It is necessary to have a comprehensive and clear understanding of the whole vehicle braking system,and through reading relevant literature on Brake-by-wire system technology to grasp the development of Brake-by-wire system.Based on the direct drive hydraulic source developed by the research group,a complete scheme of the linear control dynamic system was developed from the two main aspects of the hydraulic pressure adjustment required by the brake-by-wire system and the braking force adjustment of each brake wheel cylinder,including the selection of the direct drive hydraulic source,the use and arrangement of the three-position high-speed switching valve.It lays a good foundation for further system modeling and simulation.(2)system modeling and performance simulation.Established in the hydraulic simulation software AMESim hardware model of main components of brake system solutions,and in the MATLAB/Simulink module design of the corresponding control algorithm,using the software of joint simulation,analysis system in braking condition under different working conditions,get the corresponding vehicle braking distance and braking time data as a result,the analysis of test and verify the reliability of the simulation model design,feasibility.(3)determination of the main parameters of the system.Under the joint simulation of the system,the dynamic characteristics of the hydraulic pressure regulation part of the wheel cylinder,that is,the response characteristics of the high-speed on-off valve in the process of increasing and reducing pressure,are analyzed emphatically,and two important parameters of the response time of the three-position high-speed on-off valve and the effective flow cross-sectional area of the valve port are determined.(4)test of the principle sample.Under the condition that the system simulation is feasible,the dynamic and static response test of a bidirectional electromagnet developed by the research group is carried out,and the modification test is carried out on the existing principle samples in the laboratory,so as to verify the feasibility of the bidirectional electromagnet developed by the research group for the three-position high-speed switching valve.(5)preliminary design of three-position high-speed switching valve.In the system after the simulation and test samples to verify the feasibility,combining with the system combined the simulation of the parameters of the three high-speed on-off valve,the valve body and valve core of the preliminary design and calculation,the main application of material mechanics,mechanical design and hydraulic transmission theory knowledge related to the structure size of the valve body and valve core design calculation,at the same time for the pressure loss of flow passage and stroke as well as the important data for theoretical calculation of valve core,and finally to three high-speed on-off valve material selection are analyzed and determined,for the three high speed switch valve were developed to provide data for reference.