Abstract: Characteristics of magneto-rheological(MR) damper are analysed. A hierarchical fuzzy controller, composing of control and coordination level,is proposed for vibration control of automotive MR suspensions. In the control level, based on a hybrid control strategy of sky-hook control and ground-hook control, a semi-active fuzzy logic controller is designed for each support MR suspension system. In the coordination level, a coordination controller is designed to coordinate the four independent semi-active fuzzy controllers by adjusting their output parameters according to the system feedback.To validate the real results of hierarchical fuzzy control, a MR semi-active suspensions control and test system is set up and implemented on a mini vehicle, which is equipped with four controllable MR dampers. Test results show that the vertical vibration can be effectively reduced and the ride comfort,road holding and hanlding stability of automotive vehicle can be improved by the hierachical fuzzy controller.

Key words: Automotive vehicle, Fuzzy control, Hierarchical control, Magneto-rheological damper, Road test