Robust optimization design of vehicle braking system based on hydraulic reliability

With the rapid transformation of automobiles to new energy sources and the frequent occurrence of traffic accidents in the braking system, the research on the reliability of vehicle braking system has put forward higher requirements. Previous studies on the reliability of automotive braking systems have focused on braking temperature, vibration, and friction, while there have been few studies on the effect of brake fluid pressure on braking reliability and robust optimization of reliability design. The structure of the braking system and the behavioral parameters of the brake fluid directly affect the safety of braking. In order to reduce the impact of uncertainties in the structure of the brake system and the behavioral parameters of the brake fluid on the reliability of the hydraulic brake system, this paper proposes a new approach: A hydraulic reliability-based robust optimization design method (HRROD) of the vehicle brake system. First, a three-dimensional simplified model of the vehicle braking system was established, and the braking response time was measured by hydraulic experiments. Secondly, the brake fluid flow field of the braking system was analyzed using Fluent software to obtain the sample cell. Four surrogate model methods are used to establish the hydraulic reliability performance function model of hydraulic braking system. Finally, the HRROD of the hydraulic brake system is conducted using the weight of brake fluid and the Euclidean norm of reliability sensitivity as the optimization objective functions, and the selection scope of the design parameters and the reliability of hydraulic brake system as the constraint function. The results of the study indicate that the hydraulic reliability is improved from 0.9571 to 0.9999, a reduction in the value of the objective function by at least two orders of magnitude, and a 12.17% reduction in brake fluid weight. The finite element analysis results based on the optimal solution show that the hydraulic pressure of the braking system is increased from 4.254 to 4.472 MPa. The HRROD method and optimization results presented in this paper provide a theoretical and quantitative basis for the design and improvement of braking systems.