Magneto-rheological (MR) dampers are effective solutions in improving vehicle stability and passenger comfort. However, handling these dampers implies a strong effort in modeling and control. This research proposes an H2 controller, based on a Takagi–Sugeno (T–S) fuzzy model, for a two-degrees-of-freedom (2-DOF) one-quarter vehicle semi-active suspension with an MR damper; a system with important applications in automotive industry. Regarding performance criteria (in frequency domain) handled herein, the developed controller considerably improves the passive suspension's efficiency. Moreover, nonlinear actuator dynamics usually avoided in reported work, is included in controller's synthesis; improving the relevance of research outcomes because the controller is synthesized from a closer-to-reality suspension model. Going further, outcomes of this research are compared (based on frequency domain performance criteria and a common time domain test) with reported work to highlight the outstanding results. H2 controller is given in terms of quadratic Lyapunov stability theory and carried out by means of Linear Matrix Inequalities (LMI), and the command signal is applied via the Parallel Distributed Compensation (PDC) approach. A case of study, with real data, is developed and simulation work supports the results. The methodology applied herein can be extended to include other vehicle suspension's dynamics towards a general chassis control.

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.

This research work presents an H-infinity controller based on a Takagi-Sugeno (T-S) fuzzy model for a two-degrees-of-freedom (2-DOF) one-quarter-vehicle semi-active suspension with a magnetorheological damper where the actuator dynamics are included in the control synthesis. These dynamics enclose nonlinear damper phenomena, avoided in many other studies, and that can improve the suspension system by means of a more accurate model. The objective is to obtain a semi-active suspension that considerably improves the passive suspension efficiency based on some frequency domain performance criteria. 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. Besides, the proposed solution is compared with the recent reported work to highlight its advantages. A case of study is included and simulation work supports the results. The methodology applied herein can be extended to a half-vehicle model, and to the four wheels to have a global chassis control in order to maximise passenger comfort and vehicle stability.

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.

Automotive suspensions are important systems in improving passenger comfort and vehicle stability. Magnetorheological dampers are actually being used intensively in vehicle suspensions, improving stability and comfort by changing the damping factor in milliseconds. The difficulty about MR dampers are the highly nonlinear characteristics and inherent hysteresis that turn the damper's modeling in a complicated task. This research proposes a solution to the problem of semi-active vehicle suspension modeling through a type of Takagi-Sugeno (T-S) fuzzy model, not reported before, for a one-quarter-vehicle semi-active suspension with a Magnetorheological (MR) damper. The model has the advantage of being composed of linear subsystems, where all the linear control theory can be applied, thus further control work can be more accessible than the one applied directly to the nonlinear equations. Moreover, the new model contains all the nonlinear damper's characteristics arduous to model and avoided in other reported work. The T-S approach breaks-down the nonlinear system into linear subsystems connected by fuzzy membership functions. Simulation work included herein, provides evidence of similarity among the differential equation model and the T-S model. The present research is an introduction to important opportunity areas in suspensions performance and other vehicle dynamics, considering that T-S approach can be extended to other subsystems of the vehicle.