Design and Experimental Validation of an H∞ Observer for Vehicle Damper Force Estimation

Abstract

Abstract The real-time estimation of damper force is crucial for control and diagnosis of suspension systems in road vehicles. In this study, we consider a semi-active electrorheological (ER) suspension system. First, a nonlinear quarter-car model is proposed that takes the nonlinear and dynamical characteristics of the semi-active damper into account. The estimation of the damper force is developed through an H∞ observer whose objectives are to minimize the effects of bounded unknown road profile disturbances and measurement noises on the estimation errors of the state variables and nonlinearity through a Lipschitz assumption. The considered measured variables, used as inputs for the observer design, are the two accelerometers data from the sprung mass and the unsprung mass of the quarter-car system, respectively. Finally, the observer performances are assessed experimentally using the INOVE platform from GIPSA-lab (1/5-scaled real vehicle). Both simulation and experimental results emphasize the robustness of the estimation method against measurement noises and road disturbances, showing the effectiveness in the ability of estimating the damper force in real-time.