Aktive Schallreduktion durch digitale Zustandsregelung der Strukturschwingungen mit Hilfe piezo-keramischer Aktoren

This thesis investigates the use of structural control by modal state feedback for noise reduction of plate structures. Control forces are generated by piezo-electric actuators directly applied on the panel surface. The Finite Element Method supplies a numerical description of the noise radiating structure and the effects of the attached piezo actuators. Technical expenditures are kept low by minimizing the number of sensors and actuators used in the control system. To achieve a high control performance, a method is derived to find convenient locations for these elements. The noise reduction experiments were conducted with a clamped rectangular aluminium plate. The instantaneous state of vibration is measured and these signals are fed to a realtime computer. Control outputs are computed on basis of a modal state observer considering 10 modes in connection with a linear quadratic optimal controller. The developed active noise control achieves excellent results for the reduction of the sound pressure levels at the resonance frequencies. In a frequency range of 0... 650 Hz attenuations up to 17 dB have been measured. The use of commercially available components such as digital signal processors and piezo-electric actuators opens a wide range of future applications. (orig.)SIGLEAvailable from TIB Hannover: RN 4503(111) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman