36results 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.

The present invention discloses an active control system for rotor aerodynamic noise, relating to the technical field of rotorcraft. The blade comprises a root-cut section, a root section, a middle section, and a tip section, connected in sequence. The end of the root-cut section away from the root section is the center of the hub, and the end of the tip section away from the middle section is the blade tip. The tip section control module is installed in the tip section, and the middle section control module is installed in the middle section. The tip section control module and the middle section control module have the same structure and both include a metal frame, a shape memory alloy tube, and multiple fixing elements. The shape memory alloy tube is located in the middle of the metal frame. Multiple fixing elements are insulated and installed at different positions on the metal frame, and each fixing element is also connected to a different position of the shape memory alloy tube. The metal frame and the shape memory alloy tube both pass through the airfoil section of the blade. The fixing elements can be connected to a power supply and energize the shape memory alloy tube. The present invention can reduce or even avoid the generation of blade-vortex interference noise.

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).

A propulsion system for an aircraft includes a first hybrid power plant and a second hybrid power plant, each including a thermal engine and an electrical motor. Acoustic sensors measure an initial combined noise signature, produced by the propulsion system, including first and second noise signatures respectively generated by the first and second hybrid power plants. A controller receives a signal from the acoustic sensors and determines when an initial amplitude variation of a periodically fluctuating amplitude of the initial combined noise signature is greater than an amplitude variation threshold indicative that the initial combined noise signature generates beats. A thrust produced by the second hybrid power plant is modulated to produce a modulated combined noise signature having a modulated amplitude variation less than the initial amplitude variation. A difference in thrusts generated by the first and second hybrid power plants is compensated for.

A method of controlling an electric aircraft, the electric aircraft including a plurality of actuators, the actuators including a plurality of electric propulsion units, the method comprising: receiving force and torque commands for the electric aircraft; determining control commands for the plurality of actuators based on desired force and torque commands by solving an optimization problem, the optimization problem including a noise minimization term for minimizing noise generated by the electric propulsion units; and controlling the plurality of actuators according to the determined control commands to satisfy the force and torque commands for the electric aircraft.

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.

An aircraft control system includes: a first engine attached to an airframe of an aircraft; a second engine attached to the airframe; a first power generator connected to an engine shaft of the first engine; a second power generator connected to an engine shaft of the second engine; an electric motor driven with electric power supplied from one or both of the first power generator and the second power generator; a rotor driven with a driving force output from the electric motor; and a controller configured to estimate whether noise excess conditions have been satisfied on the basis of information for estimating noise and to change one or both of a rotation speed and a magnitude of a torque such that noise is lower than that before the noise excess conditions have been satisfied when it is estimated that the noise excess conditions have been satisfied.

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.

A method for controlling at least one rotor (5) of an air vehicle (1), the rotor (5) being configured to compensate or at least reduce a torque acting on the air vehicle (1), the rotor (5) being provided with a shroud (15), the rotational speed of the rotor and the angle of attack of at least one rotor blade (20) of the rotor being adjustable for the rotor (5), in particular independently of a further rotor (3) provided on the air vehicle (1), the method comprising a step (51) of defining at least a first pair of operating parameter values ​​and at least a second pair of operating parameter values ​​of the rotor (5), the operating parameter value pairs being capable of achieving different rotational speeds and angles of attack of the rotor at the same thrust value thereby. a step of determining (52) a first sound indicator of a first operational parameter value pair and a second sound indicator of a second operational parameter value pair, the determining step including a step of measuring sound values ​​of the rotor (5) in a test configuration; a step of storing (53) the first sound indicator and the second sound indicator together with an assignment to the respective operational parameter value pair; and a step of controlling (54) the rotor (5) during operation of the air vehicle (1) according to the first operational parameter value pair or the second operational parameter value pair with reference to the assignment stored in step c) and at least selectively as a function of the first sound indicator or the second sound indicator to be achieved.

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).

This invention discloses a drag reduction method for a rotary-body vehicle based on segmented skin rotational oscillation, comprising: determining the hydrodynamic parameters of the rotary-body vehicle when the fuselage enters the turbulent phase during cruise; determining a preset area on the rotary-body vehicle for arranging movable skin, and axially segmenting the fuselage of the rotary-body vehicle within the preset area according to a preset length; arranging movable skin outside the fuselage within the preset area, the axial length of the movable skin being the preset length; the movable skin being a cylindrical rotating body structure, with a drive mechanism arranged between it and the fuselage to drive the segment of movable skin to rotate and oscillate on the fuselage surface, and the rotational oscillation directions of adjacent movable skin segments being opposite; determining the rotational oscillation parameters of the movable skin at the initial moment when the rotary-body vehicle enters the cruise phase; during actual flight of the rotary-body vehicle, after entering the cruise phase, driving the movable skin to rotate and oscillate according to the determined rotational oscillation parameters using the drive mechanism.

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.

The application discloses a drag reduction method for spanwise vibration of sectional skin of an aerial vehicle, and comprises the following steps: determining fluid mechanics parameters of the aerial vehicle in a turbulent stage in a cruising state; determining a preset region for arranging active skin on a wing of the aerial vehicle, segmenting the wing in the preset region according to a preset length in a heading direction of the aerial vehicle, and then arranging the active skin outside the wing, wherein the length of the active skin in the heading direction is the preset length; the active skin is in a strip structure, a driving mechanism is arranged between each section of the active skin and a fuselage, the driving mechanism is used for driving the section of the active skin to perform spanwise oscillation on the surface of the wing, and the spanwise oscillation directions of adjacent active skins are opposite; determining spanwise oscillation parameters of the active skin at an initial moment when the aerial vehicle enters the cruising stage; and driving the active skin on the wing to perform spanwise oscillation by using the driving mechanism according to the determined spanwise oscillation parameters at the initial moment when the aerial vehicle enters the cruising stage.

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.

An aircraft part with a door for accessing inside an aircraft and a fuselage part includes a cavity between an upstream edge of the door in the closed position and a downstream edge of the fuselage part, the cavity opening to the outside of the aircraft part and having a bottom connected to the upstream edge of the door and to the downstream edge of the fuselage part. The aircraft part includes a chamfer on the outer face of an outer plate of the door at the upstream edge of the door, as well as possibly other technical features such as a sharp ridge and / or an add-on component, allowing for reducing noise generated by the cavity.

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.

A variable-pitch stator blade (30) for an aircraft turbomachine, comprising: - a blade (32) having an upper surface (32a) and an upper surface (32b), as well as a leading edge (32c) and a trailing edge (32d), the leading edge (32c) of the blade (32) having serrations (35) formed by alternating teeth (35a) and grooves (35b) along the leading edge (32a), - a platform (34) connected to one end of the blade (32) and defining a blade pitch axis (A), the blade (32) comprising: - a first body (36) defining the trailing edge (32d) of the blade (32), and - a second body (38) which defines at least a portion of the leading edge (32c) of the blade (32) and which is movably mounted relative to the first body (36), along the alignment axis (A). Figure for the abbreviation: Figure 4

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.