ROBUST IDENTIFICATION AND VIBRATION SUPPRESSION OF A FLEXIBLE STRUCTURE

A robust vibration suppression design involving the use of H-infinity optimal control theory is studied for a complex flexible structure. Th e digital control architecture involves noncollocated feedback utilizi ng active piezoceramic actuators and position sensor data. The modal p roperties of the multi-input, multi-output structure are first determi ned from experimental data in order to obtain an identified state-spac e model. This model forms the basis for the H-infinity vibration suppr ession design. Performance specifications are developed that obtain ad equate damping in the structure while maintaining controller integrity without the destabilization of higher modes. A controller optimized f or these H-infinity performance specifications is implemented on the a ctual test structure. Experimental structural perturbations are also e xamined in order to determine the robustness of the vibration suppress ion design. The experimental study indicates that the H-infinity desig n substantially increases damping in the targeted frequency region and conforms to predicted analytical simulations.