Date of Award

2011

Degree Type

Thesis

Department

Mechanical Engineering

First Advisor

Sawicki, Jerzy

Subject Headings

Rotors -- Dynamics, Magnetic bearings, rotordynamic, active magnetic bearing, modeling, dissimilar bearing support

Abstract

Different types of bearings have different dynamic characteristics. By using one type of bearing at one end of a rotor and another type of bearing at the other end of the rotor, it is possible to exploit the advantages of both types in the same system. One example of such combination is a bronze bushing and active magnetic bearing (AMB). In the available literature, there are examples of such systems but are not fully explored with regard to how to model the system to fully utilize both support type properties. This thesis investigates the modeling and performance of such a dissimilar bearing support system. An experimental test rig with a rotor supported at one end by AMB and at the other end by bushing is modeled with two different methods, i.e., approximate analytical approach and finite element analysis (FEA). A cost function minimizing AMB controller design method is used for both system models, resulting in two controllers of the same form. Both controllers are implemented on the experimental test rig. AMB suspension is achieved, steady state orbits are measured at several selected constant speeds. Then experimental results are compared to numerical simulations and recommendations made regarding the utilization of these dissimilar bearing supports

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