A system and method for communicating information among members of a distributed discussion group having peripheral communication devices involves communication between the peripheral communication devices and a central agent. The central agent receives and stores messages intended for at least one other group member. It creates a notice informing the at least one other group member that such a message exists and containing a channel (e.g., a hyperlink) directly to the memory location of the message. The at least one other group member may then elect to retrieve the message and may also elect to reply to the message. Such replies are transmitted from the peripheral device of the at least one other group member to the central agent, where it is stored and associated with the original message. Messages are retained in memory, thereby causing discussions to be maintained.

Centrifugal communication and collaboration method

Helicopter rotating hub mounted vibration control system for a rotary wing hub having periodic vibrations while rotating at an operational rotation frequency. The vibration control system includes a housing attachable to the rotary wing hub and rotating with the hub at the operational frequency. The housing is centered about the rotary wing hub axis of rotation and has an electronics housing cavity subsystem and an adjacent rotor housing cavity subsystem. The rotor housing cavity contains a first coaxial ring motor with a first rotor and imbalance mass and a second coaxial ring motor with a second rotor and imbalance mass. The electronics housing cavity contains an electronics control system which receives sensor outputs and electrically controls and drives the first motor and the second motor such that the first imbalance mass and the second imbalance mass are driven at a vibration canceling rotation frequency greater than the operational rotation frequency wherein the helicopter rotary wing hub periodic vibrations are reduced.

Helicopter vibration control system and rotary force generator for canceling vibrations

A system and method for actively damping boom noise within an enclosure such as an automobile cabin. The system comprises an acoustic wave sensor, a motion sensor, an acoustic wave actuator, a first electronic feedback loop, and a second electronic feedback loop. The enclosure defines a plurality of low-frequency acoustic modes that can be induced/excited by the enclosure cavity, by the structural vibration of a panel of the enclosure, by idle engine firings, and a combination thereof. The acoustic wave actuator is substantially collocated with the acoustic wave sensor within the enclosure. The motion sensor can be secured to a panel of the enclosure.

System and method for actively damping boom noise in a vibro-acoustic enclosure

A rotary wing aircraft including a vehicle vibration control system. The vehicle vibration control system includes a rotating hub mounted vibration control system, the rotating hub mounted vibration control system mounted to the rotating rotary wing hub with the rotating hub mounted vibration control system rotating with the rotating rotary wing hub. The vehicle vibration control system includes a rotary wing aircraft member sensor for outputting rotary wing aircraft member data correlating to the relative rotation of the rotating rotary wing hub member rotating relative to the nonrotating body, at least a first nonrotating body vibration sensor, the at least first nonrotating body vibration sensor outputting at least first nonrotating body vibration sensor data correlating to vibrations, at least a first nonrotating body circular force generator, the at least a first nonrotating body circular force generator fixedly coupled with the nonrotating body, a distributed force generation data communications network link, the distributed force generation data communications system network link linking together at least the first nonrotating body circular force generator and the rotating hub mounted vibration control system wherein the rotating hub mounted vibration control system and the first nonrotating body circular force generator communicate force generation vibration control data through the distributed force generation data communications network, the at least first nonrotating body circular force generator controlled to produce a rotating force with a controllable rotating force magnitude and a controllable rotating force phase, the controllable rotating force magnitude controlled from a minimal force magnitude up to a maximum force magnitude, and with the controllable rotating force phase controlled in reference to the rotary wing aircraft member sensor data correlating to the relative rotation of the rotating rotary wing hubrotating relative to the nonrotating body wherein the vibration sensed by the at least first nonrotating body vibration sensor is reduced.

Helicopter hub mounted vibration control and circular force generation systems for canceling vibrations

The computer programmable system and program product include first program instructions for actively driving a first imbalance mass concentration rotor and a second imbalance mass concentration rotor at a vibration canceling rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration to produce a rotating net force vector to inhibit periodic vibrations. The program product includes second program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a starting stopping rotation speed less than the vibration canceling rotation frequency. The system includes a fault mode control protocol for controlling a rotation of the rotors during a sensed failure of the rotating assembly vibration control system.

Computer system and program product for controlling vibrations

Described are a vibration actively reducing apparatus and a method for identifying a transfer function in the vibration actively reducing apparatus. An identification signal which is a quantization of at least one sinusoidal wave is supplied from a controller of the vibration actively reducing apparatus to a controlled vibration source in synchronization with a predetermined output sampling clock (SCo) to develop an identification vibration therefrom. The controller reads a residual vibration signal from a residual vibration detector of the actively reducing apparatus in synchronization with a predetermined input sampling clock (SCi). After read of the residual vibration signal as a time series data for each frequency, an FFT calculation is carried out for each time series data to extract a frequency component of the original sinusoidal wave. An inverse FFT calculation is, then, carried out for the result of the synthesis of each extracted frequency component to derive an impulse response as the transfer function.

Active vibration reducing apparatus and method for identifying transfer function in active vibration reducing apparatus

The vibration damping device uses a controlled oscillation source, providing an oscillation which is superimposed on the detected engine (30) vibration. The residual oscillation is detected for controlling the regulator for the controlled oscillation source together with the signal representing the detected engine vibration, the regulation algorithm containing a transmission function for the transmission path between the controlled oscillation source and the residual oscillation detector, determined via a reference signal and the residual oscillation signal.

Shigeki Satoh

Papers

Active vibration reducing apparatus and method for identifying transfer function in active vibration reducing apparatus

Active vibration damping device for motor vehicle