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Proceedings Paper

Autonomous smart sensor-electronics-actuator device for controlling periodic vibration in a structural system
Author(s): Steven L. Hardt; Marcelo C. Algrain
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Paper Abstract

The development of an intelligent sensor/electronics/actuator system is presented in this paper. The system is autonomous since it only needs some approximate knowledge of the frequency range where each vibration mode may exist. Given this information, the device senses and identifies each of the principal vibration modes, tracks them (should they drift in frequency), and generate a counter-action which suppresses each of the vibration modes to a fraction of their corresponding uncompensated magnitudes. This control action is robust since it concentrates its energy only at those frequencies where periodic disturbances are detected. The main novelty of this system is the use of phase-lock-loops and switch capacitor bandpass filters for the on-line identification and tracking of the vibration modes, and the use of feedforward and feedback signals allowing to automatically adjust the optimal gain and phase compensations for each vibration mode. This approach has many advantages: it is practical and conceptually simple; it is modular and can be easily expanded to accommodate multiple vibration modes; it can be implemented with inexpensive low-power CMOS electronics; it is versatile since it does not rely on a model of the structure for developing its controller, and it only requires some approximate notion of the frequency ranges where periodic vibration is expected. The effectiveness of this new approach is experimentally evaluated using a test unit consisting of a simple structure, accelerometers and Terfenol- D actuators. The structure is excited by driving a shaker actuator with sinusoidal voltages. The resulting periodic vibration is measured using accelerometers. Feedforward and feedback acceleration signals are processed by the electronics producing an actuator command signal. The actuator generates a counter vibration that reduces the uncompensated vibration. Attenuation levels as high as 36 dB were obtained in an actual test unit.

Paper Details

Date Published: 6 June 1997
PDF: 11 pages
Proc. SPIE 3041, Smart Structures and Materials 1997: Smart Structures and Integrated Systems, (6 June 1997); doi: 10.1117/12.275663
Show Author Affiliations
Steven L. Hardt, Univ. of Nebraska/Lincoln (United States)
Marcelo C. Algrain, Univ. of Nebraska/Lincoln (United States)


Published in SPIE Proceedings Vol. 3041:
Smart Structures and Materials 1997: Smart Structures and Integrated Systems
Mark E. Regelbrugge, Editor(s)

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