Active vibration control of a plate-like structure with discontinuous boundary conditions**Portions of this work were presented in ‘Active Control of International SpaceStation Experiment Rack Shelf Simulator Vibrations’, Proceedings of 2004 ASMEInternational Mechanical Engineering Congress, Anaheim, California, November 2004(IMECE2004-60853).

Abstract

This research involves the application of methods to actively control the vibration of aplate-like structure with discontinuous boundary conditions. The research is motivated bythe need to control vibrations on rack shelves in use on the International Space Station(ISS). Vibration of the rack shelves can adversely affect experiments being performed onthose shelves. In this work, control of a rack shelf similar to those in use on the ISS isexamined. Piezoelectric actuators bonded to the shelf structure are proposed as a methodfor controlling rack shelf vibrations. A two-dimensional asymmetric piezoelectricactuator model is first developed. The Ritz expansion method is then employed toderive the equations of motion for the combined piezoelectric actuators and rackshelf system with discontinuous boundary conditions. Model parameters from theanalytical solution are used in conjunction with experimentally obtained parametersto develop a control model for the active structure. The control model is thenused, together with a linear quadratic approach, to develop two different controlstrategies: collocated output feedback control and modal control. Results from anexperimental evaluation of the two control approaches are presented. Based onthe experimental results, the two control strategies are shown to be effective incontrolling the first several modes of the rack shelf system at frequencies below 800 Hz.