Abstract: Improved active vibration control (AVC) devices, systems, and related methods are provided herein. An AVC device includes a controller adapted to receive real-time aircraft information and adjust at least one control parameter as a function of the real-time aircraft information is provided. An AVC device is adapted to detect changes in real-time aircraft information, as the aircraft moves from a steady state to transient performance, low and high air speeds, or vice versa. An AVC system (e.g., AVCS) includes one or more sensors, one or more actuators, and a controller adapted to receive real-time aircraft information and adjust at least one control parameter. In some aspects, a method of controlling vibration within an aircraft includes receiving vibration information from at least one sensor, receiving real-time aircraft information from an avionics system, adjusting at least one control parameter used in a control algorithm, and generating a force command.

Abstract: Improved active vibration control (AVC) devices (20), systems, and related methods are provided herein. An AVC device (20) includes a controller (24) adapted to receive real-time aircraft information and adjust at least one control parameter as a function of the real-time aircraft information is provided. An AVC device is adapted to detect changes in real-time aircraft information, as the aircraft moves from a steady state to transient performance, low and high air speeds, or vice versa. An AVC system (e.g., AVCS) includes one or more sensors (22), one or more actuators (26), and a controller (24) adapted to receive real-time aircraft information and adjust at least one control parameter. In some aspects, a method of controlling vibration within an aircraft includes receiving vibration information from at least one sensor (22), receiving real-time aircraft information from an avionics system (40), adjusting at least one control parameter used in a control algorithm, and generating a force command.

Abstract: Methods/systems for monitoring an aircraft propulsion system is described. The measurement system/method provides for accurate and precise monitoring of rotating members in an aircraft vehicle propulsion system. The measuring system/method provides for a high reliability aircraft in which the propulsion dynamically rotating drive shaft system and couplings are monitored in real time. The vehicular measuring system utilizes multiple positional sensors to provide highly reliable and precise determination of the dynamic characteristics of the rotating sensor target components of the aircraft system. The relative position of the sensors is rigidly fixed externally from the rotating targets with a structural frame. The measuring system provides a misalignment measurement of the propulsion system drive shaft flexible coupling which relates to a critical performance of rotating shaft coupling in the operation of an aircraft vehicle.

Abstract: Methods and systems for monitoring rotating shaft shafts and couplings in an aircraft propulsion system is described. The measurement system/method provides for accurate and precise monitoring of a rotating shaft flexible coupling in a fixed wing aircraft vehicle propulsion system. The measuring system/method provides for a high reliability short take off vertical landing fixed wing aircraft in which the vertical propulsion dynamically rotating drive shaft system and couplings are monitored in real time. The vehicular shaft coupling misalignment measuring system utilizes multiple positional sensors to provide highly reliable and precise determination of the dynamic characteristics of the rotating sensor target components of the propulsion system drive shaft. The relative position of the sensors is rigidly fixed externally from the rotating targets with a structural frame.

Abstract: Methods and systems for monitoring rotating shaft shafts and couplings in an aircraft propulsion system is described. The measurement system/method provides for accurate and precise monitoring of a rotating shaft flexible coupling in a fixed wing aircraft vehicle propulsion system. The measuring system/method provides for a high reliability short take off vertical landing fixed wing aircraft in which the vertical propulsion dynamically rotating drive shaft system and couplings are monitored in real time. The vehicular shaft coupling misalignment measuring system utilizes multiple positional sensors to provide highly reliable and precise determination of the dynamic characteristics of the rotating sensor target components of the propulsion system drive shaft. The relative position of the sensors is rigidly fixed externally from the rotating targets with a structural frame.

Abstract: Methods and systems for monitoring rotating shaft shafts and couplings in an aircraft propulsion system is described. The measurement system/method provides for accurate and precise monitoring of a rotating shaft flexible coupling in a fixed wing aircraft vehicle propulsion system. The measuring system/method provides for a high reliability short take off vertical landing fixed wing aircraft in which the vertical propulsion dynamically rotating drive shaft system and couplings are monitored in real time. The vehicular shaft coupling misalignment measuring system utilizes multiple positional sensors to provide highly reliable and precise determination of the dynamic characteristics of the rotating sensor target components of the propulsion system drive shaft. The relative position of the sensors is rigidly fixed externally from the rotating targets with a structural frame.

Abstract: The invention provides a method/system for measuring torque. The method/system includes providing a first rotating disk having a target pattern and providing a second rotating disk having a target pattern. The method/system includes providing a first set of at least three sensors, comprised of a first disk first sensor, a first disk second sensor, and a first disk third sensor, the first set of at least three sensors for sensing the first rotating disk target pattern with the first set of at least three sensors fixed around and encompassing the first rotating disk. The method/system includes providing a second set of at least three sensors, comprised of a second disk first sensor, a second disk second sensor, and a second disk third sensor, the second set of at least three sensors for sensing the second rotating disk target pattern, with the second set of at least three sensors fixed around and encompassing the second rotating disk.

Abstract: Methods and systems for monitoring rotating shaft shafts and couplings in an aircraft propulsion system is described. The measurement system/method provides for accurate and precise monitoring of a rotating shaft flexible coupling in a fixed wing aircraft vehicle propulsion system. The measuring system/method provides for a high reliability short take off vertical landing fixed wing aircraft in which the vertical propulsion dynamically rotating drive shaft system and couplings are monitored in real time. The vehicular shaft coupling misalignment measuring system utilizes multiple positional sensors to provide highly reliable and precise determination of the dynamic characteristics of the rotating sensor target components of the propulsion system drive shaft. The relative position of the sensors is rigidly fixed externally from the rotating targets with a structural frame.

Abstract: Methods and systems for monitoring rotating shaft shafts and couplings in an aircraft propulsion system is described. The measurement system/method provides for accurate and precise monitoring of a rotating shaft flexible coupling in a fixed wing aircraft vehicle propulsion system. The measuring system/method provides for a high reliability short take off vertical landing fixed wing aircraft in which the vertical propulsion dynamically rotating drive shaft system and couplings are monitored in real time. The vehicular shaft coupling misalignment measuring system utilizes multiple positional sensors to provide highly reliable and precise determination of the dynamic characteristics of the rotating sensor target components of the propulsion system drive shaft. The relative position of the sensors is rigidly fixed externally from the rotating targets with a structural frame.

Abstract: A method for controlling end stop collisions in electro-mechanical systems including dampers or actuators. In a first aspect, a velocity-squared control method determines an end stop control signal (V.sub.end stop) based, at least in part, upon a square of the relative velocity (V.sub.inst). Preferably, the displacement (.delta..sub.end) to the end stop is also used to derive the end stop control signal (V.sub.end stop). In another aspect, a snubber control method is employed which produces a snubber control signal (V.sub.snub) based, at least in part, upon a continuous function of a snubber incursion distance (.delta..sub.z) within a snubber zone (Z). Preferably, the velocity-squared end stop and the snubber control methods operate together. When used in conjunction with an end stop control method, the snubber control method prevents end stop collisions for cases where the end stop control algorithm alone would not.

Abstract: An Active Structural Control (ASC) system (10) and method which includes a plurality of Active Vibration Absorbers (AVAs) (40) attached to a yoke (32) included within a pylon structure (28) preferably comprising a spar (38) and a yoke (32) which is located intermediate between an aircraft fuselage (20) and an aircraft engine (18) for controlling acoustic noise and/or vibration generated within the aircraft's cabin (44) due to unbalances in the aircraft engine (18). The ASC system (10) includes a plurality of error sensors (42) for providing error signals, and at least one reference sensor (49 or 50) for providing reference signals indicative of the N1 and/or N2 engine rotations and/or vibrations, and a preferably digital electronic controller (46) for processing the error and reference signal information to provide output signals to drive the plurality of AVAs (40) attached to the yoke (32).

Abstract: Actuators for active vibrational energy control systems which are frequency focused. The high-frequency cancellation function is decoupled from the low-frequency cancellation function to enable the size, force, number and placement of the actuators to be optimized. A hybrid system employing structural actuators to cancel low-frequency vibrations and speakers to cancel higher-frequency vibrations is also taught.

Abstract: An active control method and apparatus for controlling vibration or sound wherein the computational burden to adaptively update the control filter within the update model is reduced. The apparatus includes means for producing an input signal for input to the update model and the reduction block, means for generating an error sensor, and an output device for canceling sound and/or vibration at a selected location. The method uses a gradient descent algorithm such as the filtered-x LMS algorithm and replaces the long filter model with a shortened length filter model. Error signal information together with the output information from the shortened length filter model are used to update the coefficients of the control filter according to an update calculation method. The shortened filter model only contains frequency response information at the L frequencies of interest.

Abstract: An active adaptive control system and method has frequency dependent filtering with a transfer characteristic which is a function of a frequency dependent shaped power limitation characteristic maximizing usage of available output transducer authority. Band separation is provided for different tones. Power limit partitioning is provided for effectively distributing power between correction tones to maximize model performance.

Abstract: An active system for controlling vibration or sound. The system includes a method for limiting the output gain G from a gradient descent algorithm, such as an LMS algorithm, according to the relationship ##EQU1## and reducing one of first and second filter weights W.sub.1 and W.sub.0 such that G.ltoreq.G.sub.max ensuring the output canceling signal is never saturated. This eliminates the square wave shape which may impart unwanted harmonics or resonances to the dynamic system. In another aspect, the system eliminates drift of the output devices toward saturation when situations are encountered such as singularities in the quadratic performance surface. This is accomplished by applying leakage factor r(k) to a function f(k) at or near a predetermined limit to avoid saturation of the output device. The function f(k) can be the gain G or the weights W(k). Another aspect is to provide a constant, optimum, and stable adaptation rate in an LMS system by providing an optimum adaptation coefficient .mu..sub.

Abstract: An active noise and vibration control system (20) for cancellation of noise or vibration. The system (20) provides a system whereby the adaptation path and feedforward path are implemented in separate hardware. As a result, the computational burden on the digital signal processor (DSP) (28) is reduced allowing the DSP (28) to handle multiple inputs (22), error sensors (34), and transducers (32). In one embodiment, the processing of the input signal from sensor (22) takes place in a waveform generator (24) comprising a phase-locked loop, a frequency divider, a shift register, and at least one switched capacitor filter. In another embodiment the input signal processing takes place in separate feedforward circuitry including a field programmable gate array (64).

Abstract: An active mount for fixed wing applications. One aspect of the invention provides decoupling of two tones which are close in frequency by positioning the mount actuators and error sensors in the primary transmission path of the disturbance vibration and by providing adequate spatial separation between the two sets of error sensors to reduce or eliminate cross-coupling of the signals. Another aspect of the invention utilizes orthogonally positioned actuators with corresponding actuators of paired mounts being focalized for each engine.

Abstract: An active noise and vibration cancellation system with broadband control capability. A broadband disturbance signal detector positioned within a closed compartment such as an aircraft cabin or vehicle passenger compartment provides a signal representative of the frequency spectrum and corresponding relative magnitude of a broadband signal emanating from a vibrational energy source to a controller. The controller receives the broadband disturbance signal as well as error signals from error sensors which, by virtue of adaptive filters within the controller, enhance the cancellation capability of the control signals produced by one or more actuators positioned within the compartment.

Abstract: A waveform generator (20) for generating an analog wave which is synchronized with a signal from an input source (22). The waveform generator (20) includes a phase-locked loop (24) for receiving an input source signal and multiplying said signal by a multiplier. The multiplied square wave signal is then provided to a frequency divider (28) and to a first clock input (39) of a first switched-capacitor filter (29). The frequency divider (28) outputs a divided output signal that is received as an input to the phase-locked loop (25) and by the first switched-capacitor filter (35). As a result, the first switched-capacitor filter (29) outputs a first analog wave of a constant amplitude which is phase synchronized with the input source signal. This waveform generator (20) allows the 3 dB point of the filter to move as the input frequency changes.