Control of a semi-active suspension with a magnetorheological damper modeled via Takagi-Sugeno

Magnetorheological (MR) dampers have proved to be an attractive solution in improving vehicle stability and passenger comfort. However, handling with these dampers, which contain highly nonlinear phenomena, implies a strong effort in modeling and control. This research presents a Takagi-Sugeno (T-S) fuzzy model, not reported before, for a two-degrees-of-freedom (2-DOF) one-quarter-vehicle semiactive suspension with an MR damper. The objective is to prove that an MR damper, represented by the Bouc-Wen approach, is suitable for control purposes. Moreover, the model developed in [14], was reformulated into a more compact control-oriented model. The stability condition is given in terms of Lyapunov stability theory, and carried out by means of Linear Matrix Inequalities (LMI). Due to system´s fuzzy nature, the controller gain is applied via Parallel Distributed Compensation (PDC) through a static state feedback controller for each linear subsystem. The advantage of having the T-S system as a reference is that each piecewise linear system can be exposed to the well-known control theory regarding: stability, robustness, and performance. Besides, the novel model encloses the nonlinear damper phenomena, avoided in another reported work, i.e. [9], and [11], which can improve the suspension study by means of a more accurate model. A numerical case and simulation work support the results. This research introduces a more accurate control oriented model that can be applied in the suspensions performance domain towards comfort and stability improvement.