Abstract: A method, apparatus and controller for machining non-circular work pieces. The apparatus, method and controller are preferably used in combination with rotating, equipment, such as a turning center having an x-y table capable of gross movements. The apparatus includes at least one position sensor for deriving an angular position signal of the work piece, a preferably longitudinally-disposed, flexible tool holder attached to a rigid tool block which holds the machine tool, a preferably solid state vibration actuator imparting active vibrational forces to the end of the tool holder, thus vibrating the machine tool at high frequency to impart the desired ovality to the work piece, and a control system for generating the output signal to the vibration actuator. Preferably, the control system includes manually adjusted magnitude and phase thereby providing a non-circular work piece profile with the desired ovality and positioning thereof.

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: A vibration control apparatus (20) and method for a calender (18) for controlling vibration between two or more rolls (ex. 22, 24) which controls vibration induced thickness variations in a medium (27) exiting from the nip. The apparatus (20) includes a frame (19), a first and second rolls (22, 24) mounted relative to the frame (19), and a force generator (32), such as an electromechanical active actuator, servo-hydraulic actuator, controllable semi-active damper, Active Vibration Absorber (AVA), or Adaptive Tuned Vibration Absorber (ATVA), provides cancelling forces to control vibration between the first and second roll (22, 24) thereby, controlling such vibration induced thickness variations in the medium (27). Preferably, the apparatus (20) includes at least one sensor (ex.

Abstract: A flexibly-mounted active vibration absorber (AVA) which has a secondary controllable mass M.sub.3. If the passive resonance of mass M.sub.2 of the tuned absorber is insufficient to control the input vibration, a secondary mass M.sub.3 is vibrated at a frequency, amplitude and phase sufficient to make up the deficiency in mass M.sub.2. Many embodiments are described which depict variations on the first spring used for flexibly mounting the AVA, the actuators used to drive the AVA, and the attachment features for attaching to a vibrating member. Further in another aspect, means for counterbalancing the moments produced by the AVA are described.

Abstract: A hybrid active-passive system (20) for reducing noise within a passenger compartment and vibration of a fuselage of a vehicle, such as an aircraft (turboprop, turbofan, or helicopter). The hybrid active-passive system (20) includes, in combination: an active acoustic producer such as a loudspeaker (35), Active Vibration Absorber (AVA) (34), or active absorber assembly (39) for producing antinoise within the compartment (42), and a passive resonant device, such as a passive Tuned Vibration Absorber (TVA) (36), or passive TVA assembly (37) for controlling vibration of the fuselage or structural supports interconnecting the disturbance source (e.g. power plants (26), propellers (28a), gearbox (57), main rotor (28m), tail rotor (28t)) and the fuselage wall (25).

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: A method and system/apparatus implementing a non-model based Decentralized Feedforward Adaptive Algorithm (DFAA) for active vibration control of an actively-driven element, such as an Active Vibration Absorber (AVA) (24). The AVA (24)preferably includes an inertial tuning mass (42) and a voice coil assembly (46) and is contained in an active vibration control system (20) wherein the method and system/apparatus reduce vibration of a vibrating member (22) at an attachment point (26) by receiving an error signal from an error sensor (28) such as an accelerometer and a reference signal from a tachometer (32) or accelerometer (34), where the reference signal is correlated to, or indicative of the frequency content of, a primary vibration source (36) and calculating an updated output signal via an electronic controller (39) using the non-model based DFAA to dynamically drive the actively-driven element, such as AVA (24).

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.