Identification of an electro-hydraulic controllable shock absorber using black-block non-linear models

The topic of this paper is the analysis and identification of an accurate model for electro-hydraulic (EH) semi-active dampers. An EH-damper is a dynamic system, where the inputs are the elongation velocity and the requested damping level. The output is the force delivered by the damper. The results presented in this work refer to an EH-damper used for the secondary suspension in a high-speed train. EH-damper are highly non-linear systems and their accurate modeling is not a trivial task. The purpose of this paper is to present the complete damper analysis: first the damping characteristics in the speed-force domain are shown; then the estimation and analysis of the switching times are assessed; finally the black box identification approach and results are presented. The final goal is to provide an efficient model simulation oriented. It is shown that the resulting model ensures a prediction error level of 2.5%.