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Shock and Vibration
Volume 12, Issue 1, Pages 49-65
http://dx.doi.org/10.1155/2005/578381

Pre-Acting Control for Shock and Impact Isolation Systems

D.V. Balandin,1 N.N. Bolotnik,2 and W.D. Pilkey3

1Research Institute for Applied Mathematics and Cybernetics, Nizhny Novgorod State University, 10 Uljanov St., Nizhny Novgorod 603005, Russia
2Institute for Problems in Mechanics of the Russian Academy of Sciences, 101-1 Prospect Vernadskogo, Moscow 119526, Russia
3Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer’s Way, P.O. Box 400746, Charlottesville, VA 22904-4746, USA

Received 22 March 2005; Revised 22 March 2005

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Pre-acting control in shock/impact isolation systems is studied. With pre-acting control, the isolation system begins to respond to an impact before this impact has been applied to the base. The limiting performance of the isolator with pre-acting control is investigated for a single-degree-of-freedom system subject to an instantaneous impact. The isolation performance index is defined as the maximum of the absolute value of the displacement of the object to be isolated relative to the base, provided that the magnitude of the control force transmitted to the object does not exceed a prescribed value. It is shown that there is a substantial advantage in the use of pre-acting isolators over isolators without pre-action. Particular attention is given to a pre-acting isolator based on a passive elastic element (a spring) separating the object to be protected from the base. An example illustrates the calculation of the design parameters of such an isolator.