YEDİTEPE ÜNİVERSİTESİ MECHANICAL ENGINEERING DEPARTMENT SEMINAR ANNOUNCEMENT Robust Control of Rotor/Active Magnetic Bearing Systems Sina Kuseyri Mekatek Engineering Ltd. 5 January 2011, Wednesday, 16:00-16:50 Engineering Building, B306 Abstract: Rotors suspended with electromagnetic bearings are inherently unstable; therefore feedback control is an essential part of their operation. Despite the nonlinear form of the actuator (electromagnetic bearing) dynamics, plant (rotor) model is linear and time-invariant at constant rotor speed. Actuator dynamics can be linearized around an operating point using a constant bias current. Two H controllers are designed for the nominal system using different structures. The uncertainties in the system dynamics due to changes in the model parameters are two-fold: Gyroscopic forces due to different rotor speeds within the range of operation, and the changing spring stiffness of the electromagnetic bearings due to different conditions during the operation. To ensure robust stability of the closed-loop system for all possible values of parameters that can change during the operation, an H controller based on the model incorporating uncertainty in the system is designed. The limits for the allowable parameter changes for robust stability are tested and established with µ-analysis. Simulations are carried out in MATLAB-Simulink to verify the successful operation of the actual non-linear system with the linear controllers. Short Biography: Sina Kuseyri received his BSc degree in Mechanical Engineering in 1984 from Bogazici University. He received his MSc and PhD degrees in Mechanical Engineering in 1989 and 2010 from ODTÜ/Gazi University and Bogazici University respectively. Currently he is working in Mekatek Engineering Training and Consultation Ltd.