Abstract: Methods and apparatus for variable stiffness supports in aircraft testing are disclosed. A disclosed example apparatus includes a variable stiffness support including a pad to contact and support the aircraft, and a spring operatively coupled to the pad. The apparatus also includes an actuator operatively coupled to the support, a sensor, at least one memory, machine executable instructions and at least one processor. The at least one processor is to execute the instructions to determine at least one of a movement or a displacement of the pad based on information from the sensor, and control movement of the actuator based on the determined at least one movement or distance of the pad to statically support the aircraft while enabling movement of the pad above a threshold frequency.

Abstract: A system and method are provided for super-resolution imaging beyond the Rayleigh spatial resolution limit of an optical system. In the context of a system, first and second pinhole assemblies are configured to be controllably positioned. The first and second pinhole assemblies define respective pinholes and being configured to be backlit. The system also includes a collimating lens configured to collimate at least a portion of the signals passing through the respective pinholes of the first and second pinhole assemblies. The system further includes an amplitude/phase mask configured to provide amplitude and phase modulation to signals received from the collimating lens and an imaging lens configured to focus the signals received from the amplitude/phase mask upon an image plane to permit objects to be separately identified.

Abstract: Methods, systems, and apparatuses are disclosed for reducing sound level, by providing enclosures comprising enclosure walls having integral tunable resonator cavities, and reducing sound levels within the enclosure in response to detected sound levels outside of the enclosure.

Abstract: A noise cancellation system for cancelling sounds within a vehicle. The noise cancellation system includes microphones, a camera, a controller, and speakers. The microphones are disposed adjacent to occupant locations, and configured to generate microphone signals representative of noise sounds and cancellation audio sounds. The camera is configured to generate a video signal that captures head configurations of the occupants. The controller is configured to receive rotor control signals, calculate hearing locations based on tracking data of the head configurations of the occupants, and generate a speaker signals based on the hearing locations, the microphone signals, and the rotor control signals. The speakers are configured to generate the cancellation audio sounds. The cancellation audio sounds attenuate the noise sounds.

Abstract: An energy harvesting circuit is disclosed and comprises one or more electrical loads that consume direct current (DC) power, a rectifier, and a hybrid acoustic absorber. The rectifier comprises one or more active switching elements that are driven by a gate drive voltage. The hybrid acoustic absorber comprises a diaphragm and a voice coil. The diaphragm is constructed at least in part of a piezoelectric material. The piezoelectric material is configured to generate a diaphragm voltage in response to sound waves deforming the diaphragm. The diaphragm voltage is at least equal to the gate drive voltage to drive the one or more active switching elements of the rectifier. The voice coil is attached to the diaphragm and configured to generate a voice coil voltage that is less than the gate drive voltage of the one or more active switching elements.

Abstract: Embodiments herein describe mitigating flexible modes in an airframe of an aircraft by operating a battery for the aircraft as a tuned mass damper. One embodiment comprises an Unmanned Aerial Vehicle (UAV). The UAV includes a flexible airframe, a plurality of propulsors coupled to the flexible airframe that generate thrust for the UAV, a battery that provides electrical power for the plurality of propulsors, and a suspension system that suspends the battery from the flexible airframe and operates the mass of the battery as a tuned mass damper to dampen flexible modes generated in the flexible airframe during flight.

Abstract: A noise cancellation system for cancelling sounds within a vehicle. The noise cancellation system includes microphones, a camera, a controller, and speakers. The microphones are disposed adjacent to occupant locations, and configured to generate microphone signals representative of noise sounds and cancellation audio sounds. The camera is configured to generate a video signal that captures head configurations of the occupants. The controller is configured to receive rotor control signals, calculate hearing locations based on tracking data of the head configurations of the occupants, and generate a speaker signals based on the hearing locations, the microphone signals, and the rotor control signals. The speakers are configured to generate the cancellation audio sounds. The cancellation audio sounds attenuate the noise sounds.

Abstract: A testing system for monitoring a machine under test is disclosed and includes one or more high frequency sensors configured to generate a sensor signal that is representative of an operating parameter of the machine. The high frequency sensors have a required high frequency sampling rate. The testing system also includes a notification device configured to generate a notification indicating the operating parameter monitored by the high frequency sensors has exceeded a predefined threshold value and a data acquisition control module configured to monitor the high frequency sensors at a first sampling rate. The testing system also includes a monitoring control module in electronic communication with the notification device. The monitoring control module is configured to monitor the high frequency sensors at a second sampling rate that is greater than the first sampling rate and at least equal to the required high frequency sampling rate.

Abstract: An example system includes a processor and a non-transitory computer-readable medium having stored therein instructions that are executable to cause the system to perform various functions. The functions include: (i) acquiring an image of a first aerial vehicle, the image depicting an object of a second aerial vehicle prior to contact between the object and a surface of the first aerial vehicle; (ii) providing the image as input to a data-driven analyzer that is trained in a supervised setting with example images for determining a predetermined point of contact between the object and the surface of the first aerial vehicle; (iii) determining, based on an output of the data-driven analyzer corresponding to the input, an estimated point of contact between the object and the surface of the first aerial vehicle; and (iv) providing the estimated point of contact to a display system.

Abstract: A method for visual signal processing of a signal includes subdividing a signal, by a signal processor, into a selected number (n) of sets of data. The method also includes assembling the signal, by the signal processor, into an image. The image includes a matrix. The matrix includes a plurality of cells in a predetermined number (m) of columns and the selected number (n) of rows. Each cell of the matrix includes a particular color corresponding to an amplitude of a sample of the signal represented by the cell. The method also includes analyzing the image, by the signal processor, using an image detection algorithm to determine frequency information of the signal.

Abstract: An example system includes a processor and a non-transitory computer-readable medium having stored therein instructions that are executable to cause the system to perform various functions. The functions include: (i) acquiring an image of a first aerial vehicle, the image depicting an object of a second aerial vehicle prior to contact between the object and a surface of the first aerial vehicle; (ii) providing the image as input to a data-driven analyzer that is trained in a supervised setting with example images for determining a predetermined point of contact between the object and the surface of the first aerial vehicle; (iii) determining, based on an output of the data-driven analyzer corresponding to the input, an estimated point of contact between the object and the surface of the first aerial vehicle; and (iv) providing the estimated point of contact to a display system.

Abstract: An energy harvesting circuit is disclosed and comprises one or more electrical loads that consume direct current (DC) power, a rectifier, and a hybrid acoustic absorber. The rectifier comprises one or more active switching elements that are driven by a gate drive voltage. The hybrid acoustic absorber comprises a diaphragm and a voice coil. The diaphragm is constructed at least in part of a piezoelectric material. The piezoelectric material is configured to generate a diaphragm voltage in response to sound waves deforming the diaphragm. The diaphragm voltage is at least equal to the gate drive voltage to drive the one or more active switching elements of the rectifier. The voice coil is attached to the diaphragm and configured to generate a voice coil voltage that is less than the gate drive voltage of the one or more active switching elements.

Abstract: A testing system for monitoring a machine under test is disclosed and includes one or more high frequency sensors configured to generate a sensor signal that is representative of an operating parameter of the machine. The high frequency sensors have a required high frequency sampling rate. The testing system also includes a notification device configured to generate a notification indicating the operating parameter monitored by the high frequency sensors has exceeded a predefined threshold value and a data acquisition control module configured to monitor the high frequency sensors at a first sampling rate. The testing system also includes a monitoring control module in electronic communication with the notification device. The monitoring control module is configured to monitor the high frequency sensors at a second sampling rate that is greater than the first sampling rate and at least equal to the required high frequency sampling rate.

Abstract: A spin-stabilizing assembly is usable with a cylindrical barrel having a longitudinal center axis, a vertical center axis, and a distal end. The assembly includes a gimbal piece, a spinner cage, and a spinner body. A first end of the gimbal piece engages an outer diameter surface of the barrel proximate the distal end. The spinner cage is configured to engage a second end of the gimbal piece, and to pivot with respect thereto about the vertical center axis. The spinner body is disposed radially within the spinner cage and defines multiple axial vanes. The vanes, in response to impingement on the axial vanes of exhaust gases discharged from the distal end of the barrel, rotate the spinner body about the longitudinal center axis. Rotation results in impedance along the vertical center axis which minimizes vertical displacement or motion of the distal end.

Abstract: A spin-stabilizing assembly is usable with a cylindrical barrel having a longitudinal center axis, a vertical center axis, and a distal end. The assembly includes a gimbal piece, a spinner cage, and a spinner body. A first end of the gimbal piece engages an outer diameter surface of the barrel proximate the distal end. The spinner cage is configured to engage a second end of the gimbal piece, and to pivot with respect thereto about the vertical center axis. The spinner body is disposed radially within the spinner cage and defines multiple axial vanes. The vanes, in response to impingement on the axial vanes of exhaust gases discharged from the distal end of the barrel, rotate the spinner body about the longitudinal center axis. Rotation results in impedance along the vertical center axis which minimizes vertical displacement or motion of the distal end.

Abstract: An acoustic cavity tailored synthetic jet employs a body having a cavity with a wall including a taper from a first extent to an aperture. The cavity is configured to produce a matched acoustic resonance. A drive system has a piston engaged to the cavity at the first extent. The drive system and piston are configured for oscillatory motion inducing a synthetic jet at the aperture.

Abstract: A method for visual signal processing of a signal includes subdividing a signal, by a signal processor, into a selected number (n) of sets of data. The method also includes assembling the signal, by the signal processor, into an image. The image includes a matrix. The matrix includes a plurality of cells in a predetermined number (m) of columns and the selected number (n) of rows. Each cell of the matrix includes a particular color corresponding to an amplitude of a sample of the signal represented by the cell. The method also includes analyzing the image, by the signal processor, using an image detection algorithm to determine frequency information of the signal.

Abstract: Embodiments herein describe mitigating flexible modes in an airframe of an aircraft by operating a battery for the aircraft as a tuned mass damper. One embodiment comprises an Unmanned Aerial Vehicle (UAV). The UAV includes a flexible airframe, a plurality of propulsors coupled to the flexible airframe that generate thrust for the UAV, a battery that provides electrical power for the plurality of propulsors, and a suspension system that suspends the battery from the flexible airframe and operates the mass of the battery as a tuned mass damper to dampen flexible modes generated in the flexible airframe during flight.

Abstract: Described are methods and systems for broad-band active reduction of noise in target spaces, such as spaces around headrests in aircraft cabins. Systems describe herein are effective over wide frequency ranges without causing undesirable amplification at any subrange ranges. Specifically, a system comprises a speaker and a resonator, both coupled to an enclosure. The interior space of the resonator is in fluid communication with the enclosed space of the enclosure, allowing the resonator to reduce the amplitude of unwanted amplification by the audio reducing sound generated by the speaker. The amplitude is reduced in a selected frequency range, which may correspond to an expected amplification for this particular system. The resonator may partially extend into the enclosure or may be completely incorporated into the enclosure. Some examples of the resonator include a Helmholtz resonator, a passive radiator, a quarter wave resonator, a pipe resonator, and an acoustic metamaterial.

Abstract: A vibration damping system employs a component having a directionally sensitive element thereon, mounted to an aircraft, which experiences dynamic excitation that induces bending deflection in the component that will reorient the directionally sensitive element. At least one tuned mass damper is mounted on the component in an orientation in which an internal mass of the tuned mass damper is moveable such that the tuned massed damper absorbs and attenuates at least a portion of the deflective motion, to thereby suppress bending deflection of the component in the particular axial direction and generally maintain the linearity of the directionally sensitive element.