76results about "Active noise reduction system" patented technology

There is provided an acoustic black hole comprising: in a first axis, a variation from a first characteristic to a second characteristic, along a line; in a second axis different to the first axis, a variation from a first characteristic to a second characteristic, along the second axis.

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.

A method of reducing noise includes: driving a first propulsor using one or more of the first electrical motor and the first thermal engine, and driving a second propulsor of the second hybrid power plant using one or more of the second electrical motor and the second thermal engine; receiving a signal indicative of an initial combined noise signature; determining, from the signal, that an initial amplitude variation of a periodically fluctuating amplitude of the initial combined noise signature is greater than an amplitude variation threshold; modulating a thrust produced by the second hybrid power plant, by changing a power output of the second thermal engine or the second electrical motor, to produce a modulated combined noise signature having a modulated amplitude variation less than the initial amplitude variation; and compensating for a difference in thrusts generated by the first hybrid power plant and the second hybrid power plant.

Propeller synchronization device for an aircraft comprising at least two propellers (12a, 12b), at least two electrical machines (2a, 2b) for rotating the propellers, at least two speed control modules (3a, 3b) for controlling the electrical machines, so as to control the speed of the propellers, the synchronization device comprising - sensors (20) for measuring a phase shift between the propellers, - a central coordination member (14) configured to receive a phase shift instruction, to calculate a difference between the phase shift measurement and the phase shift instruction, to determine a speed instruction for the propellers from the calculated difference and to transmit the speed instruction to the speed control modules of the electrical machines, the speed control modules (3a, 3b) being configured to control the speed of the propellers as a function of the speed instruction. Figure for the abstract: 2

The invention belongs to the field of aircraft noise reduction, and discloses an aircraft cabin active noise reduction control method and related equipment, and the method comprises the steps: collecting the vibration, rotating speed, cabin sound pressure and other multi-modal data of an aircraft in real time, and carrying out the flight state classification through a pre-trained multilayer neural network model; and the current accurate working condition is determined by combining state machine conversion logic, and finally, the parameters of the feed-forward filter are dynamically adjusted through a minimum mean square algorithm to realize noise reduction. According to the method, the high-frequency component suppression capability in a multi-source coupled noise scene is effectively improved, the noise reduction efficiency is kept stable in the whole flight period, the convergence speed is improved compared with a traditional scheme, and the local optimum problem is avoided through a state self-adaptive feed-forward mechanism.

There is provided an acoustic black hole comprising: in a first axis, a variation from a first characteristic to a second characteristic, along a line; in a second axis different to the first axis, a variation from a first characteristic to a second characteristic, along the second axis.

A system and method for reducing a psychoacoustic penalty of acoustic noise emitted by an aircraft, including a plurality of propulsion assemblies coupled to the aircraft, wherein each of the plurality of propulsion assemblies includes a motor, and a plurality of blades defined by a propeller, wherein the plurality of blades can define an asymmetric blade spacing; a control subsystem coupled to the aircraft and communicatively coupled to the motor of each of the plurality of propulsion assemblies, wherein the control subsystem is operable to rotate each of the plurality of propulsion assemblies at a different frequency to modulate the acoustic power distribution of the emitted acoustic signature.

A system and method for reducing a psychoacoustic penalty of acoustic noise emitted by an aircraft, including a plurality of propulsion assemblies coupled to the aircraft, wherein each of the plurality of propulsion assemblies includes a motor, and a plurality of blades defined by a propeller, wherein the plurality of blades can define an asymmetric blade spacing; a control subsystem coupled to the aircraft and communicatively coupled to the motor of each of the plurality of propulsion assemblies, wherein the control subsystem is operable to rotate each of the plurality of propulsion assemblies at a different frequency to modulate the acoustic power distribution of the emitted acoustic signature.

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).

To provide techniques for minimizing noise generated by electric propulsion units of an electric VTOL aircraft.SOLUTION: A method of controlling an electric aircraft that has a plurality of actuators including a plurality of electric propulsion units includes: receiving force and moment commands for the electric aircraft; determining control commands for the plurality of actuators based on the desired force and moment commands by solving an optimization problem that comprises 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 meet the force and moment commands for the electric aircraft.SELECTED DRAWING: Figure 1B

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.

A control apparatus (19), which controls a drive motor (12) that drives a rotor (30) 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.

A propulsion system (11) for an aircraft (10) comprises at least first and second propulsors (30a-d), each propulsor (30a-d) being independently driven by a respective electric motor (39). The first and second propulsors (30a-d) each comprise respective rotors (36) comprising a plurality of blades (37). The rotor (36) of the first propulsor (30a) comprises a different number of blades (37) to the rotor (36) of the second propulsor (30b), and the rotors of the first and second propulsors (30a-d) each have a blade pitch varying mechanism (38).

A control apparatus (19), which controls a drive motor (12) that drives a rotor (30) 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.

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.

The invention discloses a bionic wing. The bionic wing comprises a wing main body, a bionic sawtooth front edge structure and a bionic comb-shaped rear edge structure, the bionic sawtooth front edge structure is arranged on the front edge of a wing main body and comprises a plurality of triangular sawteeth, and the triangular sawteeth are arranged in the spanwise direction of the front edge of the wing main body; the bionic comb-shaped trailing edge structure is arranged on the trailing edge of the wing main body, the bionic comb-shaped trailing edge structure comprises a plurality of comb teeth, the comb teeth are arranged in the spanwise direction of the trailing edge of the wing main body, each comb tooth is provided with an inner groove channel, and the inner groove channels extend inwards from the ends of the comb teeth; the bionic sawtooth front edge structure and the bionic comb-shaped rear edge structure both belong to feather bionic structure characteristics of an owl, so that the feather bionic characteristics of the owl are combined with the wing main body, the airflow separation noise is inhibited through the bionic sawtooth front edge structure, and the vortex shedding strength is weakened through the bionic comb-shaped rear edge structure; the aerodynamic noise is obviously reduced while the high aerodynamic efficiency of the wing main body is kept.

The invention relates to an open rotor engine. The open rotor engine includes: a rotor blade; the pitch angle of the stator blade can be adjusted through a variable pitch mechanism; the adjustable acoustic liners are arranged on the surfaces of the stator blades; the adjustable acoustic liner comprises a thin film, a perforated plate and a piezoelectric plate, and the piezoelectric plate is arranged on the thin film; the voltage adjusting mechanism is used for adjusting the voltage acting on the piezoelectric plate to adjust the force applied to the film so as to change the volume of the acoustic cavity of the acoustic liner; wherein the voltage regulating mechanism comprises a variable resistance structure, two electrode conductors and a power supply; the variable resistance structure is arranged on the inner wall of the mounting hole; the two electrode conductors are arranged on the rotating shaft at intervals and are in electric contact with the variable resistance structure; the two electrode conductors are electrically connected to the two ends of the piezoelectric plate respectively; the power supply and the variable resistance structure form an electric loop. According to the open type rotor engine, under different working conditions, the volume of the acoustic lining acoustic cavity is controlled through the piezoelectric plate, and the targeted noise reduction requirement of an aero-engine under the complex working condition is met.

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.

According to one embodiment, a flying body includes a radar, a supporter, a plurality of rotors supported by the supporter, and a controller. The rotors include a first rotor. The radar is configured to perform a detection operation and a non-detection operation. The controller is configured to perform a first control operation in a first transition from the non-detection operation to the detection operation. The controller is configured to perform a first change in the first control operation to change a rotational speed of the first rotor from a rotational speed of the first rotor in the non-detection operation. The detection operation is performed after the first control operation.

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).

An aircraft having a fuselage, an aircraft body, at least one aircraft engine system and a feature. The fuselage defining a longitudinal centerline. The at least one aircraft engine system defining an axial centerline. The at least one aircraft engine system having a nacelle and at least one rotatable propeller. The at least one rotatable propeller having a free end that is spaced radially outward from the nacelle with respect to the axial centerline. The feature shaped to alter a flow of air between the aircraft body and the at least one rotatable propeller. The feature having a continuous rounded contour when viewed along a vertical plane normal to the longitudinal centerline and intersecting the feature.

An aerial vehicle is provided which includes a propulsion unit and an airframe. The airframe includes a fuselage, a pylon and an acoustic panel. The pylon mounts the propulsion unit to the fuselage. The acoustic panel forms an exterior surface of the airframe. The acoustic panel is configured to attenuate sound propagating outside of the aerial vehicle.

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.

The present disclosure relates to improved techniques for electronic noise cancellation in aircraft and other enclosures. In some embodiments, an electronic noise cancellation device can be disposed within an aircraft. In some embodiments, the electronic noise cancellation device includes a housing that integrates one or more audio input devices 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 some embodiments, the electronic noise cancellation device is adapted to be received within a lighting socket of an overhead service component included within an aircraft enclosure. Other embodiments are also disclosed.

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.