Road disturbances rejection of a semi-active vehicle suspension

This research introduces a more accurate control oriented model that can be applied in the suspensions performance domain towards comfort and stability improvement. Active suspension based on Magnetorheological (MR) dampers is an attractive solution in improving vehicle stability and passenger comfort. These Dampers are highly nonlinear and their modeling and control is a challenge. The multi-model approach is applied to describe the highly nonlinear two-degrees-of-freedom (2-DOF) one-quarter-vehicle semi-active suspension with an MR damper. The objective is to show that an MR damper, represented by the Bouc-Wen approach, is suitable for control purposes. Passenger comfort and vehicle stability are translated into constraints on a controlled output. Therefore, the control problem aims to attenuate the effect of the road profile which is considered as an exogenous input. This problem is solved using the H∞ techniques applied to the non linear system. Due to the multi-model nature of the system description, the controller is obtained from Linear Matrix Inequalities conditions. A numerical case and simulation work support the results.