COMPARISON OF VIBRATION AMPLITUDE SUPPRESSION VS. DYNAMIC BEARING LOAD SUPPRESSION IN ACTIVE VIBRATION CONTROL OF ROTATING MACHINERY

The construction of a dynamic absorber incorporating active vibration control is described. The absorber is a 2 degree of freedom spring-lumped mass system sliding on a guide pillar, with two internal vibration disturbance sources. Both the main mass and the secondary absorber mass were acted on by direct current (d.c.) servo motors, respectively, to suppress the vibration amplitude. In this paper, a new control approach is proposed by combining fuzzy logic and neural network algorithms to control the multi-input/multi-output (MIMO) system. Firstly, the fuzzy logic controller was designed for controlling the main influence part of the MIMO system. Secondly, the coupling neural network controller was employed to take care of the coupling effect and refine the control performance of the MIMO system. The experimental results show that the control system effectively suppresses the vibration amplitude and with good position tracking accuracy.

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Test and Theory for Piezoelectric Actuator-Active Vibration Control of Rotating Machinery

Journal of Vibration and Acoustics ◽

10.1115/1.2930165 ◽

1991 ◽

Vol 113 (2) ◽

pp. 167-175 ◽

Cited By ~ 50

Author(s):

A. B. Palazzolo ◽

R. R. Lin ◽

R. M. Alexander ◽

A. F. Kascak ◽

J. Montague

Keyword(s):

Vibration Control ◽

System Reliability ◽

Active Vibration Control ◽

Piezoelectric Actuators ◽

Rotating Machinery ◽

Test Results ◽

Endurance Test ◽

Jet Engine ◽

Air Turbine ◽

Active Vibration

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 the air turbine driven-overhung rotor. The test results show significant reduction in unbalance, transient, and subsynchronous responses. Results from a 30 hour endurance test support the AVC system reliability. Various aspects of the electromechanical stability of the control system are also discussed and illustrated. Finally, application of the AVC system to an actual jet engine is discussed.

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Active Vibration Control of a Rectangular Flexible Wall of an Empty and Fluid-Filled Tank

Applied Mechanics ◽

10.1115/imece2004-61177 ◽

2004 ◽

Author(s):

S. Carra ◽

M. Amabili ◽

R. Ohayon ◽

P. M. Hutin

Keyword(s):

Vibration Control ◽

Vibration Amplitude ◽

Active Vibration Control ◽

Deformation Energy ◽

Water Levels ◽

Structural Vibration ◽

Control Input ◽

Least Mean Square ◽

Modal Shape ◽

Active Vibration

A rectangular plate bolted to a thick Plexiglas rectangular container is investigated in the case of empty and water-filled tank. A modal analysis is firstly realized in order to verify the effects of different water levels and of the free surface waves on the modal parameters and on the modal shapes. A filtered-x LMS (least mean square) adaptive feedforward algorithm is then applied to the perturbed system realizing structural vibration control in linear field with a SISO approach. Five piezoelectric PZT actuators apply the secondary control input in a nearly-collocated configuration. Their positioning is based on the knowledge on the deformation energy of the plate. The present study investigates primarily the control of the first vibration mode, but second and third modes are also experimentally studied. Satisfactory reductions (up to about 45 dB on the second mode measured on Channel 4) are reached for vibration amplitude of the three modes investigated in absence of water. For each modal shape, a particular effectiveness of the optimally placed actuators clearly appears. The introduction of water in the tank reduces the effectiveness of control of the first mode (maximum 5.5 dB of reduction of the vibration amplitude), but the five control channels show a more global uniform effectiveness.

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Piezoelectric Pushers for Active Vibration Control of Rotating Machinery

Journal of Vibration and Acoustics ◽

10.1115/1.3269856 ◽

1989 ◽

Vol 111 (3) ◽

pp. 298-305 ◽

Cited By ~ 20

Author(s):

A. B. Palazzolo ◽

R. R. Lin ◽

R. M. Alexander ◽

A. F. Kascak ◽

J. Montague

Keyword(s):

Feedback Control ◽

Vibration Control ◽

Active Control ◽

Active Vibration Control ◽

Rotating Machinery ◽

Nasa Lewis Research ◽

Control Methods ◽

Test Rig ◽

Related Theory ◽

Active Vibration

The active control of rotordynamic vibrations and stability by magnetic bearings and electromagnetic shakers has 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. This paper contains analyses which extend quadratic regulator and derivative feedback control methods to the “prescribed displacement” character of piezoelectric pushers. The structrual 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. The paper presents results performed on the NASA test rig as preliminary verification of the related theory.

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