Stiffness Damping Sensitivity Analysis and Integrated Modeling of Electro-Hydraulic Servo Load Simulator for High-Speed Rail Active Shock Absorber

The Electro-Hydraulic Load Simulator (EHLS) plays a critical role in testing the dynamic and fatigue performance of Active Shock Absorbers (ASA). Nevertheless, challenges arising from the ASA actively tunable stiffness and damping characteristics adversely affect the loading accuracy and control stability. This research develops an integrated model of the coupling EHLS and ASA, and analyzes the effects of variations in stiffness and damping characteristics on the dynamic performance and stability margin of the EHLS. The integrated model is developed to obtain the open-loop transfer function from the controller output to the EHLS system response. Based on the integrated model, a numerical analysis model was constructed using MWORKS simulation software. The effects of the stiffness damping characteristics of the ASA on EHLS system performance — including crossover frequency, stability margin — were analyzed under conditions of individually and simultaneously varying stiffness and damping parameters. The simulation results demonstrate that system performance exhibit differential sensitivity to variations in damping and stiffness characteristics. The result of this research offer practical guidance for the engineering design of high-performance EHLS systems aligned with ASA characteristics.