The test-rig consists of a slim shaft, two active piezoelectric ball bearings and up to two discs. The disks and bearings can be moved freely on the shaft by using clamping sets. In this way, the behavior of various lightly damped elastic rotors can be reproduced and investigated. For example, a design can be chosen that resembles a Jeffcott-rotor or a jet engine with strong gyroscopic behavior. The shown set-up of the rotor has two resonances in the operating range. Furthermore, the test bench shows rotational damping due to the use of clamping sets. For investigation and control, the displacements of the two disks and the two bearing forces are measured in the 2D plane. The use of Simulink-Realtime XPC allows a simple and fast implementation of control approaches.
In the past, most common control approaches such as LQR/LQG, Integral Force Feedback, FxLMS, µ-Synthesis, and Gain-Scheduled H∞ have been implemented. It was found that a combination of Integral Force Feedback and FxLMS yields the best results regarding vibration isolation, which is equal to the elimination of the bearing forces. It remains to be seen how the transient performance of the control, so for rotor run-ups and run-outs, can be improved. Another research topic is the investigation of the relevance and, if necessary, elimination of the so-called force-free resonances, which occur when the bearing forces are completely eliminated by the active control. The project AMOS aims at the consideration of the bending energy to eliminate these force-free resonances.
