Research On The Following Characteristic Test Of Electronic Hydraulic Brake System For Automobile

With the rapid development of China's automotive industry and people's living standards, car plays a more and more importan role in people living, how to design reliable braking system is always an important task of automotive research institutions. EHB system as a multi-functional braking system, integrate function of all the traditional brake system as a whole. Make up the deficiency of traditional brake system, the traditional brake system, the brake master cylinder make the piston move, transmiss the brake fluid to all brake wheel cylinder, only to a certain extent before the distribution of braking is realized, can not very well to each brake wheel, difficult to make full use of individually controlled, and EHB make a high pressure accumulatorn as the driving force , with PWM drive high-speed on-off valves, with the way of closed-loop feedback control pressure cylinder, it will collected the various information of sensor to control unit ECU, ECU decision-making out the best brake power of system needed, fully utilize the surface braking force, achieve good braking effect and the superiority of the EHB system determines itself will have broad development prospects.Quick and stable pressure follow characteristics of wheel cylinder is the based of realizing the control function ABS, EBD, TCS, this paper EHB system wheel cylinder pressure follow characteristics have been investigated by adjusting control PID controller, each wheel cylinder pressure, signal and target given wheel cylinder pressure constantly, and according to compare comparison results of feedback signal and actual wheel cylinder pressure to real-time adjust the output of the electromagnetic valve PWM value, adjusts the brake fluid flow line, eventually make the cylinder pressure value to achieve the desired target. The actual wheel cylinder pressure can fast and steady response, it can gain some basic parameters and algorithm and lay a solid foundation for the real car test. This study includes the following respects content results:The first chapter mainly introduced the research background of line control technology, EHB system EHB system performance characteristics, research status and development direction of electron hydraulic brake, and the significance of building EHB experiment platformThe second chapter constructs the overall scheme of the electronic hydraulic brake system. This paper puts forward overall scheme of electronic hydraulic brake system. make functional designof the electronic brake unit (ECU) and hydraulic brake actuator (HCU) Analyzed the electronic hydraulic brake system, high pressure accumulator provide the power for the hydraulic control system ,with the way of PWM control high-speed switching valves to control wheel cylinder pressure, realize the wheel independent control of each of cylinder.using the Solidworks software to draw three-dimensional graph of EHB system,lays good foundation of EHB test bench for actual building.The third chapter of researching on test bench of electro-hydraulic brake system,Electronic hydraulic brake test bench department mainly divided into hydraulic actuators (HCU) and the electronic control unit (ECU). This article design and select the function and characteristics of the two units respectively. including hydraulic brake actuator research: selection of the hydraulic supply unit high pressure accumulator and electric hydraulic pump, selection and design of the hydraulic control unit. including a high-speed switch valve, and election and matching of auxiliary units storage box, brake pipe, air cleaner and pressure sensors. development of Electronic control unit (ECU) include: ECU single-chip microcomputer CPU chip choice and single-chip microcomputer data collect and design of input channel and single-chip microcomputer output channel decide etc. Then through the second chapter of the test bed layout design of the experimental stage build up. Test bench of electro-hydraulic braking system were studied in the fourth chapter,,The experimental study on the bench test is a very important method, also is very necessary. Through researching on follow characteristic test of electronic hydraulic brake system for automobile, we can obtain some basic parameters and algorithm and lay a solid foundation. In this paper, firstly researching on controlling algorithm of following characteristic test of electronic hydraulic brake system and control algorithm based on PID is validated by experiment, be monitored by xPC data acquisition device, finally setting the PID scope of the optimum controller parameters. Through the observation proof on PID control wheel cylinder pressure to follow in good condition, wheel cylinder pressure signal of practical feedback can follow the given signal steadily and rapidly .