Semi-active control of vehicle suspension with magneto-rheological dampers

Semi-active H∞ control of vehicle suspension with magneto-rheological (MR) damper is studied in this paper. First, an experiment is conducted on an MR damper prototype subjected to cyclic excitation. Then, a polynomial model is adopted to characterize the dynamic response of the MR damper. Such a model has an advantage that it can represent the inverse dynamics of the MR damper analytically, so that the desired output in the open-loop control scheme can be realized easily. Finally, a static output feedback H∞ controller which utilizes the measurable suspension deflection and sprung mass velocity as feedback signals for active vehicle suspension is designed. The active control force is realized with the MR damper using the obtained polynomial model. A quarter-car suspension model is considered in this paper for analysis and simulation. The proposed scheme is further validated by numerical simulation under random excitation. Simulation results showed that the designed static output feedback H∞ controller realized by the MR damper can achieve good active suspension performance.