Synthesis and fuzzy logic control of flexible rotor systems with active magnetic suspensions

This dissertation presents the approaches on the analysis and synthesis of magnetic suspension controller design and digital implementation. A finite element (FE) based, flexible shaft supported by magnetic bearings (MB) is first studied in a closed loop system with a conventional controller. The FE model of the rotor system is employed to develop a magnetic suspension compensator to provide reliable operation and good disturbance rejection from zero to nominal operating speed. Based on the fully nonlinear magnetic bearing model, a later model fuzzy logic controller is utilized to obtain an improved performance a of high order nonlinear system for a large motion tracking problem. Analytical formulation of a fuzzy logic controller (FLC) is given based on Tagaki-Sugeno-Kang (TSK) architecture to deal with all nonlinearities of the system. An algorithm for approximating the TSK model to the Mamdani model is then developed. Finally, a digital signal processor (DSP) is used to implement the controller on a real time basis. A method to use the LabVIEW package for auxiliary signal processing as well as a friendly graphical user interface is developed.