On the noise reduction of active sidewall aircraft panels using feedforward control with embedded systems

Keeping aircraft interior noise on an acceptable level is important in modern aircraft design. There is a trade-off in the achievable transmission loss of aircraft and the additional weight of the insulation provision, especially at low frequencies. The present work focuses on narrow banded noise sources due to the rotational speed of rotors. So-called smart linings, augmented with actuators and sensors shall reduce the transmitted noise by feedforward control. Their feasibility to reduce noise at frequencies below 500 Hz (excited by a loudspeaker array) has already been tested successfully at DLR on test panels and in a fully equipped test aircraft on ground. This paper is a discussion of the recent activities to simplify the control strategies in a way that they can be implemented on small embedded systems with limited performance. In the future, such microprocessor units enable the integration of the actuators, sensors and control algorithms directly into smart lining modules, having a positive effect on maintainability and weight footprint of the smart panels.