Real-time feedforward control of low-frequency interior noise using shallow spherical shell piezoceramic actuators

• Published in: Smart materials and structures Vol. 8; no. 5; pp. 579 - 584
• Main Authors: Jayachandran, V, King, Patrick, Meyer, Nancy E, Li, Florence J, Petrova, Maria, Westervelt, Melissa A, Hirsch, S M, Sun, J Q
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.10.1999; Institute of Physics
• Subjects: Acoustics; Aeroacoustics and atmospheric sound; Aeroacoustics, atmospheric sound; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Noise: its effects and control; Physics; Internal noise; Large pipe; Experimental study; Loudspeaker; Real time; Low frequency; Noise control; Modeling; Piezoelectric ceramics; Active system; Piezoelectric actuators; Testing equipment; Feedforward; Cylindrical shell; Aircraft
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/0964-1726/8/5/308

Active control of sound in aircraft and automobile interiors is a problem that has received considerable attention. Active control techniques are typically applied at low frequencies where passive techniques become ineffective. Different feedforward control techiques are available that use loudspeakers or structural sources as control elements. Active noise cancellation (ANC) is a popular method that works on the principle of "anti-noise" or the destructive interference of sound waves. The severe weight and space limitations encountered in the design of commercial aircraft motivate us to investigate alternative speaker designs that are lightwieght, low profiled, and reasonably efficient at low frequencies. This paper demonstrates the use of RAINBOW and THUNDER actuators as acoustic control sources in the real-time control of low frequency harmonic interior noise. The former actuator drives a flat acoustic piston while the latter drives a conventional speaker cone. The low-profiled and lightweight nature of these actuators makes them suitable for aircraft applications. The two devices have been used successfully for active noise cancellation inside a duct and a cylindrical enclosure. This paper presents results of the real-time noise control experiments. (Example materials: PVC pipe and aluminum cylinder.)