Active Control of the Structural Intensity in Beams Using a Frequency-Domain Adaptive Method

Abstract

This paper presents an active control method which consists of minimizing the active part of the structural intensity aiming at reducing the overall vibration level in beams. The basic idea behind this strategy is that the control forces dissipate the input power due to the perturbing forces, thus preventing the structure from having to vibrate in order to dissipate the incoming energy. A frequency-domain adaptive structural intensity control method (ASIC) is used. The method is investigated using a simple example consisting of an aluminum beam which is fitted at one end with a quasi-anechoic termination (sandbox) and has the other end free. Numerically simulated and experimental results are presented. The numerical simulation uses a state-space model which was identified using experimental data. Results are compared with those obtained minimizing measured vibration directly, and with results using the instantaneous wave amplitudes as error signals in time-domain LMS control schemes. In the preliminary experimental results, the ASIC method and the method that controls the wave amplitudes outperformed one another at different frequencies. At frequencies where the power-flow-based methods performed well, their performance was equivalent to that of the direct control of vibrations. The relative advantages and disadvantages of the different control methods are discussed.

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References

Arruda, J. R. F. and Dehandschutter, W. 1996. “Strategies for Active Vibration Control Using a Structural Power Flow Approach,” Proceedings of the 21st International Conference on Noise and Vibration Engineering (ISMA 21), Leuven, Belgium, 653-666.

Arruda, J. R. F. , Moreira, F. J. O. and Pereira, A. K. A. 1997. “Comparing Feedback Vibration Control and Feedforward Power-Flow-Based Control Strategies Using a Simple Plate Example,” Proceedings of the 1997 International EAA Symposium on Active Control of Sound and Vibration, Budapest, Hungary, 75-92.

Elliott, S. J. , Stothers, I. M. and Nelson, P. A. 1987. “A Multiple Error LMS Algorithm and Its Application to the Active Control of Sound and Vibration,” IEEE Transactions on Acoustics, Speech, and Signal Processing, ASSP-35(10): 1423-1434.

Fuller, C. R. , Elliot, S. J. and Nelson, P. A. 1996. “Active Control of Vibrations,” Academic Press, USA.

Gibbs, G. P. , Fuller, C. R. and Silcox, R. J. 1995. “Active Control of Flexural and Extensional Power Flow in Beams Using Real Time Wave Sensors,” Proc. the Int. Symposium on Active Control of Sound and Vibration, Newport Beach, CA, USA, 909-925.

Halkyard, C. R. and Mace, B. R. 1993. “A Wave Component Approach to Structural Intensity in Beams,” Proc. of the 4th Int. Congress on Intensity Techniques, Senlis, France, 183-190.

Haykin, S. 1996. “Adaptive Filter Theory,” 3rd edition, Prentice Hall, Upper Saddle, NJ, USA.

Liu, K. and Skelton, R. E. 1993. “Q-Markov Covariance Equivalent Realization and Its Application to Flexible Structure Identification,” Journal of Guidance, Control, and Dynamics, 16(2):308-329.

Meirovitch, L. 1990. “Dynamics and Control of Structures,” John Wiley and Sons, New York, NY, USA.

10.

Moreira, F. J. O. and Arruda, J. R. F. 1997. “Model Identification using ERA and Q-Markov Cover: An Experimental Example,” 6th Brazilian Symposium on Dynamic Problems of Mechanics, DINAME 97, 242-244.

11.

Noiseaux, D. U. 1970. “Measurement of Power Flow in Uniform Beams and Plates,” J. Acoust. Soc. America, 47(1), 238-247.

12.

Widrow, B. and Stearns, S. D. 1985. “Adaptive Signal Processing,” Prentice Hall, Englewood Cliffs, NJ, USA.