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Robust Control of Rotor/Active Magnetic Bearing Systems
Sina Kuseyri
Mekatek Engineering Ltd.
5 January 2011, Wednesday, 16:00-16:50
Engineering Building, B306
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.