Sliding Mode Control of Flexible Rotor Using Magneto Rheological Squeeze Film Damper
This study aims to control the vibration of a flexible rotor system using magneto rheological squeeze film damper (MR-SFD). To evaluate the performance of damper, Bingham plastic model is used for MR fluid and the hydrodynamic equation of MR-SFD is presented. The remarkable point about this equation is the necessity of using numerical methods to solve it. These methods are too costly and impossible especially in the simulation of complex rotors and implementation of model base controllers. To fix this issue, an estimated equation is used in this paper for pressure distribution throughout the damper. By integration of this expression, hydrodynamic forces of MR-SFD are calculated as an algebraic equation. Furthermore, sliding mode controller is chosen as robust control method by considering the structural and parametric uncertainties of the system. Study time and frequency responses of flexible rotor in presence of these controllers show a good performance in reducing vibration of shafts midpoint. The results for the open loop system also indicate that changing the stiffness coefficient of elastic foundation and the temperature of MR fluid (as two uncertainties of system) strongly affects the outputs while using sliding mode controllers well increases the robustness of the system.