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  • 1985-1989  (4)
  • 1
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    Piezoelectric pushers for active vibration control of rotating machinery (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The active control of rotordynamic vibrations and stability by magnetic bearings and electromagnetic shakers was discussed extensively in the literature. These devices, though effective, are usually large in volume and add significant weight to the stator. The use of piezoelectric pushers may provide similar degrees of effectiveness in light, compact packages. Analyses are contained which extend quadratic regulator, pole placement and derivative feedback control methods to the prescribed displacement character of piezoelectric pushers. The structural stiffness of the pusher is also included in the theory. Tests are currently being conducted at NASA Lewis Research Center with piezoelectric pusher-based active vibration control. Results performed on the NASA test rig as preliminary verification of the related theory are presented.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA, Lewis Research Center, Rotordynamic Instability Problems in High-Performance Turbomachinery, 1988; p 87-110
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Active control of transient rotordynamic vibration by optimal control methods (1988)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Although considerable effort has been put into the study of steady state vibration control, there are few methods applicable to transient vibration control of rotorbearing systems. In this paper optimal control theory has been adopted to minimize rotor vibration due to sudden imbalance, e.g., blade loss. The system gain matrix is obtained by choosing the weighting matrices and solving the Riccati equation. Control forces are applied to the system via a feedback loop. A seven mass rotor system is simulated for illustration. A relationship between the number of sensors and the number of modes used in the optimal control model is investigated. Comparisons of responses are made for various configurations of modes, sensors, and actuators. Furthermore, spillover effect is examined by comparing results from collocated and noncollocated sensor configurations. Results show that shaft vibration is significantly attenuated in the closed loop system.
    Keywords: CYBERNETICS
    Type: ASME PAPER 88-GT-73
    Format: text
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  • 3
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    Test and theory for piezoelectric actuator-active vibration control of rotating machinery (1989)
    In:  Other Sources
    Details
    Publication Date: 2019-07-27
    Description: The application of piezoelectric actuators for active vibration control (AVC) of rotating machinery is examined. Theory is derived and the resulting predictions are shown to agree closely with results of tests performed on an air turbine driven-overhung rotor. The test results show significant reduction in unbalance, transient and sub-synchronous responses. Results from a 30-hour endurance test support the AVD system reliability. Various aspects of the electro-mechanical stability of the control system are also discussed and illustrated. Finally, application of the AVC system to an actual jet engine is discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: Biennial ASME Conference on Mechanical Vibration and Noise; Sept. 17-21, 1989; Montreal; Canada
    Format: text
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  • 4
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    Piezoelectric pushers for active vibration control of rotating machinery (1989)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: The active control of rotordynamic vibrations and stability by magnetic bearings and electromagnetic shakers have been discussed extensively in the literature. These devices, though effective, are usually large in volume and add significant weight to the stator. The use of piezoelectric pushers may provide similar degrees of effectiveness in light, compact packages. Tests are currently being conducted with piezoelectric pusher-based active vibration control. Results from tests performed on NASA test rigs as preliminary verification of the related theory are presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: ASME, Transactions, Journal of Vibration, Acoustics, Stress, and Reliability in Design (ISSN 0739-3717); 111; 298-305
    Format: text
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    NASA TECHNICAL REPORTS
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