Road profile estimation for suspension systems based on hybrid strategy using ℋ∞ and Nonlinear Unknown Input Observers

This paper proposes a road profile estimation approach based on the already existing sensors of the DS7 Crossback suspension system. The proposed technique is based on a structure of Luenberger and Nonlinear Unknown Input Observers. Utilizing the stability theory of nonlinear observers in conjunction with Linear Matrix Inequalities (LMI), this study provides conditions for the existence of the Nonlinear Unknown Input Observers. These observers serve a dual purpose by not only providing approximate state estimations but also bolstering the resilience of the system against unknown disturbances and nonlinearities. The validity of the approach is confirmed through the presentation of numerical simulation results.