| Brake system modeling is an important content in the research of vehicle dynamics. It is of great significance in the analysis of vehicle dynamic characteristics, development of chassis control system and design of controller.The vehicle brake system constitution is different from each other according to the configuration. As the Anti-lock Braking System (ABS) has become one of the basic configurations in vehicle and is the basis of other brake system structures, the research is carried out based on ABS structure. A high-precision hydraulic brake system model is built, to improve the accuracy of tire pressure and brake force estimation. It also provides model and analysis foundation for anti-lock brake control, traction control and vehicle stability control.To make the structure of dissertation clear and ease the analysis and discussion, the structural features of hydraulic brake system that will be discussed is represented in the second chapter. The system structure and working principle is introduced briefly, which provides necessary knowledge preparation and structure description for the modeling of hydraulic brake system.In the third chapter of dissertation, the mechanism model of the brake pedal, vacuum booster, master cylinder, hydraulic regulator, hydraulic brake pipes and wheel cylinders are discussed and the mathematical description of the dynamic components is given. As the hydraulic pressure regulator model has great impact on model accuracy, therefore, this part of work is carried out on the experimental platform for specific hydraulic pressure regulator. It is mainly divided into two parts. First, the model of open / close solenoid valve is simplified to throttle model, and the relationship between the valve flow ratio and flow coefficient, master cylinder pressure, wheel cylinder pressure, and accumulator is deduced based on the Bernoulli equation. Second, according to the hydraulic principle, hydraulic pump and wheel cylinder characteristic curve, the static models of the pump and the wheel cylinder are obtained.The parameters of hydraulic brake system model include parameters like geometry, brake fluid parameters (brake fluid density, elastic modulus), structural parameters (quality, volume, spring stiffness, valve orifice area), and parameters to reflect the components performance (friction, damping, valve discharge coefficient, etc). How to identify the parameters of a specific brake system model is a key problem in the brake system research. This dissertation first uses actual vehicle brake circuit, vehicle dynamics simulation software and real-time simulation system to build an experimental platform for hydraulic brake system test and analysis. Based on this, the parameter identification method using the actual output and model output error sum of squares minimum criterion is discussed and the identification of the parameter results are given. Simulation and experimental results show that the brake system represent in the dissertation has high precision in the process of"Apply","Hold"and"Release".Road adhesion coefficient estimation is extremely important to determine control parameters in brake control. It is an important part of vehicle state estimation. By means of a simplified hydraulic brake system model, the road adhesion coefficient estimation method is discussed based on the wheel cylinder pressure. The estimating method is certificated on the experiment platform and the simulation results show that the method is feasible and is real-time.
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