Active Noise Control

Abstract

AbstractThe new generation of aircraft require innovative solutions for the reduction of cabin noise, which can deal with new designs of the aircraft and are also able to withstand new requirements for lightweight vehicles. Active control technologies offer interesting lightweight solutions for the reduction of aircraft cabin noise at low audio frequencies, which can be used effectively in combination with passive sound insulation treatments. In the introductory section, the basic principles of active noise control are presented. Also, the principal characteristics of feed‐forward and feedback control architectures are reviewed with reference to tonal and broadband random disturbances. The following three sections introduce the principal control approaches that can be implemented in aircraft. The active control of cabin noise is first discussed. In particular, the effects produced by feed‐forward active noise control and active noise and vibration control systems are investigated. Also, the possibility of implementing active headrests is discussed. The control of vibration transmission from aircraft engines and helicopter gearbox systems is then reviewed. In particular, active vibration control and adaptive tunable vibration absorber technologies are examined. Finally, the active control of sound transmission through the fuselage double wall structure is analyzed. Two approaches are considered: active structural acoustic control and decentralized active vibration control.