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EP-4250284-B1 - ACTIVE NOISE CONTROL SYSTEM FOR AN AIRCRAFT

EP4250284B1EP 4250284 B1EP4250284 B1EP 4250284B1EP-4250284-B1

Inventors

  • WANDEL, MARTIN
  • THOMAS, CHRISTIAN
  • MACHUNZE, WOLFGANG
  • FRIEDBERGER, ALOIS

Dates

Publication Date
20260506
Application Date
20220321

Claims (13)

  1. Active noise control system (100), comprising: a foil (110), configured to be mounted to an interior panel of an aircraft (200); wherein the foil (110) comprises: a plurality of conductive tracks (111); a driver arrangement (112); a plurality of actuators (113); and a plurality of sensors (114); wherein each of the plurality of actuators (113) is connected to the driver arrangement (112) via at least one of the plurality of conductive tracks (111); wherein each of the plurality of sensors (114) is connected to the driver arrangement (112) via at least one of the plurality of conductive tracks (111); wherein each of the sensors (114) is configured to sense vibrations and/or acoustic sounds and to send measurement signals (115) to the driver arrangement (112); wherein the driver arrangement (112) is configured to analyze the measurement signals (115) and to generate and send control signals (116) to the actuators (113) so that the actuators generate vibrations and/or acoustic sounds that counteract the vibrations and/or acoustic sounds sensed by the sensors (114); wherein the driver arrangement (112) comprises a plurality of driver devices (112); wherein the plurality of driver devices (112) are distributed over the foil (110); and wherein each of the driver devices (112) is responsible for a defined subset of the plurality of sensors (114) and of the plurality of actuators (113) close to the corresponding driver device (112).
  2. The active noise control system (100) of claim 1, wherein at least one of the plurality of actuators and/or at least one of the plurality of sensors is a micro electro-mechanical system device (120), MEMS-device (120).
  3. The active noise control system (100) of claim 1 or 2, wherein at least one of the plurality of actuators and/or at least one of the plurality of sensors is a capacitive micromachined ultrasonic transducer (130), CMUT (130).
  4. The active noise control system (100) of any one of the preceding claims, wherein at least one of the plurality of actuators (113) is a loudspeaker.
  5. The active noise control system (100) of any one of the preceding claims, wherein at least one of the plurality of sensors (114) is a microphone.
  6. The active noise control system (100) of any one of the preceding claims, wherein at least one of the plurality of actuators (113) and/or at least one of the plurality of sensors (114) is a piezo electric element.
  7. The active noise control system (100) of claim 6, wherein the piezo electric element is made from an inorganic compound comprising lead zirconate titanate.
  8. The active noise control system (100) of any one of the preceding claims, wherein at least one of the plurality of actuators (113) and/or at least one of the plurality of sensors (114) is formed by a rigid bottom film (141) having a first metal layer (144) and a top film (142) having at least one second metal layer (145); wherein the bottom film (141) is arranged directly on the foil (110); wherein the top film (142) is spaced apart from the bottom film (141) by a plurality of spacers (143); wherein the top film (142) is designed to vibrate and thereby generate the vibrations and/or acoustic sounds; wherein each of the at least one second metal layer (145) together with the first metal layer (144) builds a capacitor.
  9. The active noise control system (100) of any one of the preceding claims, wherein each of the plurality of driver devices (112) comprises an integrated single-chip microchip configured to analyze the measurement signals (115) and to generate and output the control signals (116).
  10. The active noise control system (100) of any one of the preceding claims, wherein the foil (110) builds a mesh having cutouts.
  11. The active noise control system (100) of any one of the preceding claims, wherein the foil (110) is a flexible and/or stretchable foil.
  12. Aircraft (200), comprising: a fuselage (210); a cabin (220); and an active noise control system (100) according to any one of the preceding claims.
  13. The aircraft (200) of claim 12, wherein the active noise control system (100) is attached to an inner wall of the fuselage (210) or to an interior panel within the cabin (220); wherein the active noise control system (100) is configured to detect noise within the cabin (220) and to cancel the noise by generating noise components counteracting the detected noise.

Description

TECHNICAL FIELD The present disclosure relates to active noise control systems in general, and in particular to active noise control system for aircraft applications as well as an aircraft with such an active noise control system. TECHNICAL BACKGROUND Oftentimes, acoustic noise is undesired. For example, in aircraft cabins, vibrations of the fuselage of the aircraft and of interior components lead to disturbing noise within the cabin. Such vibrations may for example result from the operation of the turbines or propellers or from drag forces exerted onto the aircraft during flight, and are mechanically propagated to the cabin, where they produce acoustic noise that may be unpleasant for passengers and crew. Active noise control or noise cancellation systems are in principle known in the art. Such systems usually utilize microphones and loudspeakers, where the microphones measure the sounds or rather the noise to be canceled. The loudspeakers are then commanded to create counter sounds which are, for example, opposite in phase to the noise to be cancelled. These noise control system are, e.g., known for headphones. In aircraft applications, in order to implement such systems, currently relatively large actuators (such as loudspeakers) and sensors (such as microphones) are used which are distributed in regions of the aircraft, where noise cancellation is desirable. These components, as well as the harnesses used to connect them, are relatively large and heavyweight. Therefore, in order to meet the weight requirements, only a relatively small amount of such actuators and sensors can be used. US 2020 / 227 020 A1 describes an acoustic element including a nanovoided polymer layer having a first nanovoid topology in an unactuated state and a second nanovoid topology different than the first nanovoid topology in an actuated state. Capacitive actuation of the nanovoided polymer layer, for instance, can be used to reversibly control the size and shape of the nanovoids within the polymer layer and hence tune its sound damping characteristics or sound transduction behavior, e.g., during operation of the acoustic element. An acoustic element may be configured for passive or active sound attenuation. US 2021 / 195 335 A1 describes an audio system including at least one sound generation device having at least an acoustic transducer; and an electronic integrated circuit. A communication bus is connected to the at least one sound generation device and is configured to communicate a digital signal comprised of one or more audio streams and control signals. A power bus is connected to the at least one sound generation device. The acoustic transducer includes at least one of the following groups: a membrane and an acoustic modulator; or a membrane, acoustic resonator, and acoustic coupler. The electronic integrated circuit is constructed and arranged to receive the digital signal and generate an analog electric signal to operate the acoustic transducer to generate an audio signal in accordance with the control signal. Gardonio P: "Review of active techniques for aerospace vibro-acoustic control", Journal of Aircraft, AIAA- American Institute of Aeronautics and Astronautics, Inc, US, vol. 39, no. 2, 1 March 2002, pages 206-214, XP001102152, ISSN: 0021-8669 presents a review of active techniques for aerospace vibro-acoustic control. The mechanisms of airborne or structure-borne sound generation and transmission in aerospace vehicles are briefly reviewed. The main approaches of passive and active noise/vibration control are summarised, and three examples of active systems that have already been developed into practical aerospace applications are briefly described. The actuator, sensor, and control system requirements for aerospace applications are discussed. Yang Xiaopeng ET AL: "Review of flexible microelectromechanical system sensors and devices", Precis. Eng. Nano. Prec. Eng, 27 April 2021 (2021-04-27), pages 25001-25001, XP055953244 describes that, today, the vast majority of microelectromechanical system (MEMS) sensors are mechanically rigid and therefore suffer from disadvantages when used in intimately wearable or bio-integrated applications. By applying new engineering strategies, mechanically bendable and stretchable MEMS devices have been successfully demonstrated. The article reviews recent progress in this area, focusing on high-performance flexible devices based on inorganic thin films. The common design and fabrication strategies for flexibility and stretchability are addressed and the recent application-oriented flexible devices are summarized. US 2010 / 252 677 A1 describes an aircraft that includes a cabin in which at least part of the space is demarcated by trim panels and the cabin is provided with a system for the active control of ambient noise. Each trim panel is either an active panel including actuators powered by the active noise control system or a passive panel without such actuators. In addition, the t