Bolt Beranek and Newman Inc.

Bbnt Solutions Llc.

Applied Physical Sciences Corp.

Bbn Corporation

Bruce Stuart Murray

Paul James Remington

James A McConnell

Bruce M Abraham

Evan F Berkman

James Edwin Barger

Richard Madden

Ronald Bruce Coleman

John Scott Knight

Howard C Noble

Daniel A Roy

Wilma W Quinn

Daniel L Nelson

James A Mcconnell

A coherent sound source is provided for marine seismic surveys. An underwater sound projector for producing time-harmonic waveforms comprises two pistons positioned on either side of an electro-magnetic force generator substantially having mechanical and magnetic symmetry about its geometric center thereby creating a virtual node to substantially cancel reaction loads that occur when the pistons are actuated. The underwater sound projector optionally also includes control systems to improve the fidelity of the force generator, provide pressure compensation to the pistons, finely adjust the static position of the pistons, and change the depth and roll when it is configured as tow body. A plurality of underwater sound projectors can be configured in an array. A load-bearing umbilical can connect the underwater sound projectors to a ship, transmit electrical power to each array element and serve as a duplex data transmission medium to route commands from the ship to the projector and report machinery status to the ship.

Coherent sound source for marine seismic surveys

A coherent sound source is provided for marine seismic surveys. An exemplary underwater sound projector comprises a plurality of pistons actuated by an electromagnetic force generator having components comprising a stator, armatures, electrical coils, and permanent magnets. The pistons and the components are arranged to create mechanical and magnetic symmetry about a geometric center of the projector to reduce reaction loads that occur when the pistons are actuated. The stator and the armatures have magnetic poles that employ a tapered geometry. The projector optionally includes control systems to improve the fidelity of the force generator, provide pressure compensation to the pistons, finely adjust the static position of the pistons, and/or change the depth and roll when the projector is configured as a tow body. A plurality of such projectors can be configured in an array. An umbilical can connect the projectors to a vessel, transmit electrical power and compressed gas to each array element and/or provide a data transmission medium between the projector and the vessel.

A compliant stator motor is disclosed. In one implementation, the motor () includes a rotor (), a stator () having main and auxiliary windings, an outer motor case (), and a group of isolators () positioned between the stator () and outer motor case () to enhance forces applied to the foundation () due to excitation of the auxiliary windings. In another implementation, the motor () includes a rotor (), a stator () including main and auxiliary windings, linear bearings () configured to constrain a motion of the stator () to an axial direction, and isolators () connected to the stator () and configured to enhance axial forces applied to the foundation due to excitation of the auxiliary windings.

Compliant stator

A mechanical amplifier includes first and second amplifier mounting pads () and first and second sensor mounting pads (). At least one of the first and second amplifier mounting pads () receives a load or displacement. The first and second sensor mounting pads () connect to the first and second amplifier mounting pads () via flexible connecting members. A sensor () may connect to the first and second sensor mounting pads to measure the amount of load or displacement.

Mechanical amplifier systems and methods

There is disclosed multiple embodiments of a predictive active compensation system for dampening vibration in an optimum manner employing feedback control wherein stiffness of dampening material is adjusted on a continuous and dynamic basis to ensure that relative displacement between vibrating machine or object and its foundation does not exceed particular limits including limits preventing impact between object and foundation. In these disclosed systems and methodologies of the present invention the foundation may also be subjected to movement. Further disclosed are computer plots of mathematical models on which embodiments of the present invention are based, thereby demonstrating efficacy of the present invention.

Predictive active compensation systems

A method and apparatus to cancel gear vibration and noise by imposing a canceling drive torque or force on a driven gear set. Sensors receive information and produce an error signal representative of the vibration and/or noise generated at meshing gears. The error signal indicative of vibration and/or noise information is provided to a control mechanism that processes the noise information to generate a corresponding drive torque. The drive torque corresponding to the noise information is applied to a drive shaft or through a power supply to reduce vibration and noise of the gear assembly at gear meshing frequencies.

Active cancellation of noise at gear mesh frequencies for a gear

In the active pneumatic mount disclosed herein, a bellows or other flexible sealing means is utilized for containing a volume of pressurized gas which supports the weight of the equipment which is to be isolated. Within the pressurized volume is a means defining a chamber having an opening for receiving an acoustic transducer. An acoustic transducer is mounted in that opening for generating, in the pressurized volume, oscillatory pressure variations which reduce dynamic pressure variations induced by the vibrations which are to be blocked. The space within the chamber is vented to the pressurized volume, thereby to equalize the static pressure in the space.

Active pneumatic mount

The electromagnetic force generator disclosed herein employs first and second elongate magnetic cores having transversely facing pole faces at each end, the cores being essentially parallel with pole faces aligned and facing. Between each pair of aligned pole faces is a relatively moveable core. A suspension provides a compliant mechanical connection between the moveable and elongate cores. The moveable cores are polarized by a permanent magnet mounted between the elongate cores and polarized along an axis paralleling the length of the elongate cores. Respective windings are provided around the elongate cores. A.c. energization of the windings creates a corresponding vibratory force between the movable cores and the elongate cores.

Electromagnetic force generator

In the electromagnetic transducer disclosed herein, first and second magnetic core structures are oriented in opposition with a space therebetween. In the space between the core structures, an armature is provided for completing magnetic circuits for both of the core structures with respective gaps. Spring means normally centers the armature structure between the core structures so that the respective gaps are nominally equal. On each of the core structures there is provided a first winding and a second winding. The first windings are connected in series to a supply of direct current thereby to bias the magnetic circuits and the second windings are connected to a source of alternating current with the second windings being installed or phased so that one of them aids the corresponding first winding while the other opposes the corresponding first winding.

Electromagnetic transducer

In the underwater sound source disclosed herein, rigid diaphragms are provided at opposed ends of a hollow shell, the periphery of each of the diaphragms being sealed to the shell. Respective spring means operating between the shell and each of the diaphragms allows axial displacement of the diaphragm in response to external pressure. A lightweight magnetic armature structure is connected to each of the diaphragms and opposed electromagnetic core structures provide magnetic circuits which link each of the armature structures across respective gaps. Further spring means are provided for centering each of the armature structures between the respective magnetic core structures. By appropriately energizing windings on the magnetic core structures, the armatures together with their respective diaphragms are caused to oscillate.

Growing community of inventors

Winchester, MA, United States of America

Bruce Stuart Murray