Vibration neutralizers are effective vibration control devices at a single frequency. If they can compensate for drift in the excitation frequency by adjusting their stiffness the performance can be improved, and the range of problems to which they can be applied is broadened. This paper considers a beam-like adaptive vibration neutralizer, and it is shown that the stiffness of the device and hence its natural frequency can be significantly altered by varying the beam cross-section. Several different beam configurations are investigated and the rate of change of stiffness as a function of beam separation is calculated for each configuration. The results are validated by some simple experiments. Real-time stiffness control of a beam-like tuneable neutralizer is also demonstrated both by computer simulation and experiment. The neutralizer is subjected to swept sine excitation over a six-second period and the tuned condition is maintained throughout the excitation period. The efficacy of using a nonlinear fuzzy logic controller is compared with the use of a simple proportional controller.

Issue Section:
Technical Papers
Keywords:
fuzzy control, vibration control, vibrations, proportional control, nonlinear control systems, real-time systems
Topics:
Excitation, Fuzzy logic, Separation (Technology), Stiffness, Control equipment, Vibration
1.
Long
,
T.
,
Brennan
,
M. J.
, and
Elliott
,
S. J.
,
1997
, “
Design of Smart Machinery Installations to Reduce Transmitted Vibrations by Adaptive Modifications of Internal Forces
,”
Proc. Inst. Mech. Eng. Part I
, ,
12
, pp.
215
–
228
.
2.
Brennan
,
M. J.
,
1997
, “
Vibration Control Using a Tunable Vibration Neutralizer
,”
Proc. Inst. Mech. Eng., Part C: J. Mech. Eng. Sci.
,
221
, Part C, pp.
91
–
108
.
3.
Von Flotow, A. H., Beard, A, and Bailey, D., 1994, “Adaptive Tuned Vibration Absorbers: Tuning Laws, Tracking Agility, Sizing and Physical Implementations,” Noise-con 94, 1, pp. 437–454.
4.
Den Hartog, J. P., 1934, Mechanical Vibrations, Dover.
5.
Brennan, M. J., 1998, “Actuators for Active Vibration Control-Tunable Resonant Devices,” 4th Euro Conf on Smart Structures and Materials, pp. 41–48.
6.
Hodgson, D. A., and Duclos, T. G., 1990, “Mount with Adjustable Length Inertia Track,” US Patent 4969632.
7.
Walsh
,
P.
, and
Lamancusa
,
J.
,
1992
, “
A Variable Stiffness Vibration Absorber for the Minimization of Transient Vibration
,”
J. Sound Vib.
,
158
, No.
2
, pp.
195
–
211
.
8.
Wang, K., and Lai, J., 1995, “Control of an Adaptable Dynamic Absorber for Transient Vibration Suppression,” 2nd Conf Recent Advances in Active Control of Sound & Vibration.
9.
DeBedout
,
J. M.
,
Franchek
,
M. A.
,
Bernhard
,
R. J.
, and
Mongeau
,
L.
,
1997
, “
Self tuning Helmholtz Resonators
,”
J. Sound Vib.
,
202
, pp.
109
–
123
.
10.
Long T, 1996, “Adaptive Control of Tuned Vibration Neutralisers,” PhD thesis, ISVR University of Southampton.
11.
Abe
,
M.
,
1996
, “
Rule Based Control Algorithm for Active Tuned Mass Dampers
,”
J. Eng. Mech.
,
122
, pp.
705
–
713
.
12.
Lai
,
J. S.
, and
Wang
,
K. W.
,
1996
, “
Parametric Control of Structural Vibrations via Adaptable Stiffness Dynamic Absorbers
,”
ASME J. Vibr. Acoust.
,
118
, pp.
41
–
47
.
13.
Kidner
,
M.
, and
Brennan
,
M. J.
,
1999
, “
Improving the Performance of a Vibration Neutraliser by Actively Removing Damping
,”
J. Sound Vib.
,
221
, pp.
587
–
606
.
14.
Tse, F., Morse, I, and Hinkle, R., 1978, Mechanical Vibrations: Theory and Applications, 2nd ed., Prentice & Hall.
15.
Kidner, M. R. F., 1999, “An Active Vibration Neutraliser,” PhD thesis, ISVR University of Southampton.
16.
Rao, S., 1995, Mechanical Vibrations, 3rd ed., Addison-Wesley Publishing Company.
Copyright © 2002
 by ASME
You do not currently have access to this content.