Active vibration control of rotorbearing systems utilizing piezoelectric pushers /
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| Other Authors: | , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1990.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | This research developed theories and conducted tests for incorporating piezoelectric pushers as actuator devices for active vibration control. It started from a simple model with the assumption of ideal pusher characteristics and progressed to sophisticated electro-mechanical models with non-ideal pushers. Effects on system stability due to the non-ideal characteristics of piezoelectric pushers and other elements in the control loop were investigated. Application of modal space optimal control with output feedback to the control of rotordynamic transient vibrations from blade loss has been investigated. The transient vibration level of rotordynamic systems was shown, in theory, to be significantly reduced by the optimal control method. Three active vibration control (AVC) theories (the optimal control theory, the pole placement theory, and the uncoupled velocity-feedback theory) were extended to treat the special prescribed "internal' displacement character of piezoelectric pushers. The uncoupled velocity-feedback damper theory was then tested and compared to the experimental results. The discrepancy between predicted and measured results most likely arises from the nonlinearity and hysterisis in the voltage-deflection and load-deflection characteristics of the pushers, and from the neglect of the structured damping of the piezoelectric pusher. Theories of soft-mounted piezoelectric pushers as actuators for AVC of rotorbearing systems, were developed to minimize the effects to the rotor from the excited casing modes. Correlation between unbalance response test and theory showed very good agreement for velocity feedback AVC and fair agreement for position feedback AVC. Theories for the electro-mechanical model, incorporating the mechanical structure (rotor) and the transfer functions of control devices (piezoelectric pushers, drivers, etc.), were developed to predict the system instability onset gain. The electro-mechanical model successfully predicted the lowest three modes and the unstable mode identified during the test... |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Mechanical engineering." |
| Physical Description: | xviii, 229 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |