ACTIVE CONTROL OF AIRCRAFT CABIN NOISE USING COLLOCATED STRUCTURAL ACTUATORS AND SENSORS

This paper describes preliminary laboratory experiments conducted on a turboprop aircraft fuselage to reduce propeller-induced tonal cabin n oise and vibration. Piezoelectric elements were grouped to construct a long one-dimensional array of actuators bonded to the fuselage in the main sound transmission path at the propeller footprint. Strain gauge s and accelerometers were used as alternative sensor devices and were distributed along the actuator in a collocated arrangement. The array of actuators and sensors was designed to work in unison, generating a smart closed-loop array of control elements that possess wave-number f iltering properties for the less critical acoustic modes of the cabin. The control system was tested in the laboratory using a simplified pr opeller pressure loading distribution. Promising results were obtained , as the closed-loop control system proved to be unconditionally stabl e and capable of significantly attenuating the fuselage vibration in t he transmission path at the critical blade passage frequencies. Moreov er, although only one array of control elements was used, interior noi se reduction was also observed during the tests, proving the merit of the concept.