Active Cabin Noise and Vibration Control for Turboprop Aircraft Using Multiple Piezoelectric Actuators

The Active Structural Acoustic Control (ASAC) technique was applied to reduce propeller-induced noise and vibration in the passenger cabin of the deHavilland Dash-8 turboprop aircraft. Piezoceramic elements were used for structural actuation while velocity feedback of the fuselage was achieved through the use of accelerometers. Three actuators comprised of segmented piezoelectric elements were designed with the objective of reducing the noise and vibration levels at the propeller Blade Passage Frequency (BPF). Twelve accelerometers were grouped to effectively form three sensors. Second order classical compensators were designed for each of the three dominant control loops in order to achieve high gain at the BPF, rendering the closed-loop system insensitive to disturbances at the control frequency. The propeller acoustic field on the port side of the aircraft was simulated in a laboratory using a speaker-ring consisting of four loudspeakers. The control system was tested using this acoustic field, producing noise attenuation as high as 28 dB in the interior, and fuselage vibration reduction as high as 16 dB.