Fuzzy logic control of an automotive suspension system : Active suspensions

The aim of the work described in the paper was to illustrate the application of fuzzy-logic techniques to the control of a continuously variable damping automotive suspension system. The study was analytical and involved the use of a multibody (MBS) model of a passenger car. The model included the dominant vehicle nonlinearities in the kinematic behaviour and the force characteristics, as well as realistic representations of the actuating, sensing and control systems of the variable damping system. The fuzzy-logic controller has four inputs involving both vehicle response parameters and driver inputs and one output being the selected damping rate. The compositional rule of inference was applied in the controller described, and two methods of defuzzification were used, mean of maxima and centroid. The paper describes the model and controller used in the study and discusses the vehicle response results obtained from a range of road and driver input simulations. Finally, some conclusions as to the success of the control design techniques and resultant controller are drawn.