26results about "Active noise reduction system" patented technology

A system and method for controlling a VTOL aircraft to minimize acoustic noise. In a hover mode, the aircraft may be controlled to utilize a blade pitch angle and corresponding angle of attack range which minimizes variations in the boundary layer separation location to a point or narrow region, which reduces noise generation. The propeller blades used in the system are configured to have a reduced or no shift of the point of flow separation on the airfoil as a function of angle of attack during the hover mode. The blade design may trade off overall blade efficiency in exchange for the reduced noise during hover.

This disclosure relates to improved techniques for electronic noise cancellation in aircraft and other enclosures. In certain embodiments, an electronic noise cancellation device can be installed in an aircraft. In certain embodiments, the electronic noise cancellation device can include a housing that integrates: one or more audio input devices that are configured to receive an input audio signal; one or more audio output devices configured to output a noise cancellation signal; one or more lighting components; and at least one connector that enables the electronic noise cancellation device to be coupled to an overhead service component of the aircraft. In certain embodiments, the electronic noise cancellation device is adapted to be received in a lighting socket of the overhead service component included within an aircraft enclosure. Other embodiments are disclosed.

- Aircraft part comprising an access door and a fuselage part forming a cavity, configured to reduce noise generated by the cavity. - The aircraft part (1) comprising a door (2) for access to the interior of the aircraft and a fuselage part (3) is provided with a cavity (6) formed between an upstream edge (8) of the door (2) in the closed position and a downstream edge (9) of the fuselage part (3), the cavity (6) opening outwards from the aircraft part (1) and comprising a bottom (10) connected to the upstream edge (8) of the door (2) and to the downstream edge (9) of the fuselage part (3), the aircraft part (1) comprising a chamfer (17) on the external face (14B) of an external plate (14) of the door (2) to the upstream edge (8) of the door (2), as well as possibly other technical features such as a sharp edge (18) and / or an added part (25), allowing to reduce the noise generated by the cavity (6).

The present application belongs to the technical field of aircraft skin, and relates to an aircraft elastic porous medium skin, a plurality of hole bodies are prefabricated on the skin, an organ pipe type nozzle is installed in the hole body, the organ pipe type nozzle is connected with a jet control system for providing a heat medium for the organ pipe type nozzle; the organ pipe type nozzle comprises an inlet section, a resonance section, an intermediate section and an outlet section connected in sequence; the inlet section is provided with an incidence hole, the resonance section is provided with a resonance hole, the intermediate section is provided with an intermediate hole, and the outlet section is provided with an emission hole which is a diverging hole; the incidence hole, the resonance hole and the intermediate hole are all cylindrical holes, and the diameters of the incidence hole, the resonance hole and the intermediate hole gradually decrease. The elastic porous medium skin is used to induce the slip and micro-cavitation effect of unsteady boundary layer fluid, and the geometric parameters of the control hole are controlled, so that the self-adaptive boundary layer flow state is greatly reduced, the frictional resistance is reduced, and the outer lining has the characteristics of noise reduction, and has the scattering and absorption effect on sound waves.

An acoustic panel for an aircraft providing noise attenuation over a wide frequency band by combining two resonators, and acoustic panel manufacturing method. The acoustic panel includes a rear skin, a cellular structure, an intermediate layer including perforations, a cellular structure, a cellular structure and a resistive skin including perforations. The acoustic panel combines quarter-wave resonators with Helmholtz resonators to provide noise attenuation over a wide frequency range.

A control apparatus, which controls a drive motor that drives a rotor installed in an electrical aircraft, instructs the drive motor to selectively operate in at least two motor-control modes. The at least two motor-control modes include a flying motor-control mode for causing the electrical aircraft to fly, and a cleaning motor-control mode for cleaning the rotor. The control apparatus controls, in the cleaning motor-control mode, the drive motor such that a rotational frequency of the drive motor is lower than a predetermined human-audible frequency range.

Vertical take-off and landing (VTOL) aircraft can provide opportunities to incorporate aerial transportation into transportation networks for cities and metropolitan areas. However, VTOL aircraft may be noisy. To accommodate this, the aircraft may utilize onboard sensors, offboard sensing, network, and predictive temporal data for noise signature mitigation. By building a composite understanding of real data offboard the aircraft, the aircraft can make adjustments to the way it is flying and verify this against a predicted noise signature (via computational methods) to reduce environmental impact. This might be realized via a change in translative speed, propeller speed, or choices in propulsor usage (e.g., a quiet propulsor vs. a high thrust, noisier propulsor). These noise mitigation actions may also be decided at the network level rather than the vehicle level to balance concerns across a city and relieve computing constraints on the aircraft.

An active noise control system (100) and an aircraft (200) having such an active noise controls system (100) are disclosed. The active noise control system (100) comprises a foil (110), configured to be mounted to an interior panel of an aircraft (200). 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). 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). 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). Each of the sensors (114) is configured to sense vibrations and / or acoustic sounds of the foil and to send measurement signals (115) to the driver arrangement (112) 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).

This disclosure relates to improved techniques for electronic noise cancellation in aircraft and other enclosures. In certain embodiments, an electronic noise cancellation device can be installed in an aircraft. In certain embodiments, the electronic noise cancellation device can include a housing that integrates: one or more audio input devices that are configured to receive an input audio signal; one or more audio output devices configured to output a noise cancellation signal; one or more lighting components; and at least one connector that enables the electronic noise cancellation device to be coupled to an overhead service component of the aircraft. In certain embodiments, the electronic noise cancellation device is adapted to be received in a lighting socket of the overhead service component included within an aircraft enclosure. Other embodiments are disclosed.

The application discloses a ducted fan based on a bionic structure, which comprises a driving motor, a propeller and a duct body; the driving motor is used for driving the propeller to rotate; the propeller is arranged in a space surrounded by the duct body; a bird feather-shaped groove is arranged on an inner wall surface of the duct body, a plurality of groups of the bird feather-shaped grooves are arranged in a circumferential direction of the surface wall of the duct body, the plurality of groups of the bird feather-shaped grooves are arranged in an axial direction of the duct body, and groove angles of adjacent bird feather-shaped grooves are opposite in sign; the bird feather-shaped groove is introduced on the surface of the duct body, the gas flow of the wall surface of the duct body is improved, and the overall operation noise is reduced; moreover, the ducted fan has a good application prospect in noise reduction compared with a reference fan, the original duct profile design appearance and the cooperation relationship between the propeller and the duct are not changed, and the ducted fan has more transformability.

To provide a flying body capable of highly accurate detection, a controller, a control program, and a control method.SOLUTION: A flying body comprises a radar, a support portion, a plurality of rotors supported by the support portion, and a controller. The plurality of rotors includes a first rotor. The radar can perform detection operation and non-detection operation. The controller can perform the first control operation in the first transition from the non-detection operation to the detection operation. The controller performs a first change in the first control operation to change the rotational speed of the first rotor from the rotational speed of the first rotor in the non-detection operation. The detection operation is performed after the first control operation.SELECTED DRAWING: Figure 1

A method for reducing a noise level and a vibration level by determining an initial noise level, determining an initial vibration level, measuring a first angular position of a first blade of a first engine based on a reference blade of the first engine, measuring a second angular position of a second blade of a second engine based on a reference blade of the second engine, calculating based on the first angular position and the second angular position a first rotational speed of the first engine and a second rotational speed of the second engine to reduce the initial noise level and the initial vibration level, transmitting the first rotational speed to the first engine and the second rotational speed to the second engine, and executing a command to set the first engine to the first rotational speed and the second engine to the second rotational speed.

The invention relates to a process (9) for setting the phase between engines (3) of a multi-engine aircraft (A) comprising a master engine (3a) and at least one slave engine (3b), each engine (3) being coupled to a fan or propeller, in order to minimize cabin noise and vibrations, the process (9) comprising the following steps: a) performing a first synchronization step (91) intended to minimize vibrations; and b) performing a second fine tuning step (92) intended to minimize noise, such a process enabling the vibration and noise emitted by the multi-engine aircraft to be reduced in a simple and reliable manner.

This invention discloses a method for controlling high Mach cavity noise. A spoiler is positioned upstream of the leading edge along the airflow direction, with the leading angle of the spoiler being smaller than its trailing angle. This invention targets high Mach (3Ma) cavity flow, achieving suppression of aerodynamic noise and realizing a significant noise reduction effect (approximately 12 dB in the most severe conditions).

A method for activating at least one rotor (5) of an aerial vehicle (1), wherein the rotor (5) is designed to compensate for, or at least reduce, a torque acting on the aerial vehicle (1), the rotor (5) is provided with a casing (15), and wherein a rotational speed of the rotor and an angle of attack of at least one rotor blade (20) of the rotor can be set for the rotor (5), in particular independently of a further rotor (3) provided on the aerial vehicle (1), comprises the following steps: fixing (51) at least a first pair of operating-parameter values and at least a second pair of operating-parameter values for the rotor (5), which each specify different rotational speeds and angles of attack of the rotor for an identical thrust value thereby achieved, determining (52) a first speed-of-sound number for the first pair of operating-parameter values and a second speed-of-sound number for the second pair of operating-parameter values, wherein the determination comprises measuring a sound value for the rotor (5) in a test setup, storing (53) the first and second speed-of-sound numbers, including assignment to the respective pair of operating-parameter values, and activating (54) the rotor (5) during operation of the aerial vehicle (1), with reference to the assignment stored in step c) and on the basis of the at least first or second speed-of-sound number selectively to be achieved, according to the first pair of operating-parameter values or the second pair of operating-parameter values.

Unmanned aircraft have aligned forward and aft propulsion systems possessing different performance and / or noise characteristics. According to some embodiments, unmanned aircraft have a forward engine and a forward tractor propeller and an aft engine and an aft pusher propeller. Selected ones of forward and aft propulsion systems will thus be provided to have greater and lesser operational flight performance characteristics and greater and lesser noise signature characteristics, respectively, as compared to the other. For example, the forward propulsion system may be provided with the greater operational flight performance and / or noise signature characteristics as compared to the aft propulsion system, while conversely the aft propulsion system may be provided with a lesser flight performance and / or noise signature characteristics as compared to the forward propulsion system.

A vibration suppression system for utilizing surface actuation of an aircraft includes an at least one aircraft control surface operably-coupled with an at least one flight control actuator, and a controller such that the controller is configured to determine a flight mode of the aircraft, calculate a predicted vibration in the aircraft based on the determined flight mode of the aircraft, and control the at least one flight control actuator connected to the at least one aircraft control surface of the aircraft such that the actuation of the at least one aircraft control surface counteracts the predicted vibration in the aircraft based on the determined flight mode of the aircraft.

The invention relates to a process (9) for setting a phase between the engines (3) of a multi-engine aircraft (A) to minimize cabin noise and vibration, the aircraft (A) comprising a master engine (3a) and at least one slave engine (3b), each engine (3) being coupled to a fan or a propeller, the process (9) comprising the steps of: a)performing a first synchronization step (91) aimed at minimizing vibration; and b) performing a second fine-tuning step (92) aimed at minimizing noise. Such a process makes it possible to reduce, in a simple and reliable manner, the vibrations and noise emitted by a multi-engine aircraft.

A muffler includes: a first plate having a plurality of holes; a second plate with a plurality of holes; the first plate is mounted above the second plate at a spacing of less than or equal to 2 mm in the whole area with the openings of the first plate and the second plate; and an additional feature selected from the group consisting of a back cavity and an acoustic membrane covering the aperture of the first plate. In embodiments, the holes of the first plate are neither directly aligned with the holes of the second plate. In an embodiment, the first plate is mounted over the second plate at a pitch that does not exceed twice a Stokes boundary layer thickness estimated at a first predetermined frequency. The muffler may be disposed on a blade surface of a fan or wind turbine. The silencer can also be used for noise reduction of a centrifugal blower or a vehicle.

Systems and methods according to embodiments of the present technology vary engine throttle and flight control surfaces (such as high-lift devices, which can include flaps and / or slats) during takeoff, climb, approach, and / or landing of a supersonic aircraft to reduce noise. A representative computing device automatically controls thrust output of the propulsion system according to a schedule of thrust output, such that the thrust output remains below levels at which the jet exhaust becomes supersonic, and such that noise is reduced to comply with noise regulations or other limitations. The computing device also automatically controls the position and configuration of flight control surfaces to compensate for the reduced thrust and to maintain an appropriate climb and / or descent rate.

A sound adjustment method of an aircraft is provided. The sound adjustment method includes acquiring a sound signal; acquiring flight state information of the aircraft; amplifying the sound signal having a first frequency or lower when the flight state information indicates ascending or descending of the aircraft; and amplifying the sound signal having a second frequency or lower when the flight state information indicates level flight of the aircraft. The second frequency is lower than the first frequency. The amplified sound signal is output.

A method for controlling at least one rotor (5) of a flight vehicle (1), wherein the rotor (5) is configured to compensate for or at least reduce a torque acting on the flight vehicle (1), the rotor (5) being provided with a shroud (15), and wherein a rotational speed of the rotor and an angle of attack of at least one rotor blade (20) of the rotor are adjustable for the rotor (5), in particular independently of a further rotor (3) provided on the flight vehicle (1), comprises the following steps: determining (51) at least a first pair of operating parameter values and at least a second pair of operating parameter values of the rotor (5), which respectively specify different rotational speeds and angles of attack of the rotor at the same thrust value achieved thereby, determining (52) a first sound index for the first pair of operating parameter values and a second sound index for the second pair of operating parameter values, wherein the determining comprises measuring a sound value of the rotor (5) in a test arrangement, storing (53) the first and second sound indices with assignment to the respective pair of operating parameter values, and controlling (54) the rotor (5) during operation of the flight vehicle (1), with reference to the assignment stored in step c) and as a function of the at least first or second sound index to be selectively achieved, in accordance with the first pair of operating parameter values or the second pair of operating parameter values.

A rotor assembly may include a first rotor mounted on a first drive shaft, and a second rotor mounted on a second drive shaft. The second drive shaft may be concentrically mounted on the first drive shaft. The rotor assembly may include a first motor operatively connected to the first rotor, and a second motor operatively connected to the second rotor. In one example, the first motor may be configured to rotate the first rotor in a first direction, and the second motor may be configured to rotate the second rotor in a second direction. Additionally the rotor assembly may include a controller configured to operate the first and second motors independently to control a blade crossing azimuth based on an angle of inflow.

A vibration suppression system for utilizing surface actuation of an aircraft includes an at least one aircraft control surface operably-coupled with an at least one flight control actuator, and a controller such that the controller is configured to determine a flight mode of the aircraft, calculate a predicted vibration in the aircraft based on the determined flight mode of the aircraft, and control the at least one flight control actuator connected to the at least one aircraft control surface of the aircraft such that the actuation of the at least one aircraft control surface counteracts the predicted vibration in the aircraft based on the determined flight mode of the aircraft.