Patents by Inventor Robert E. Stewart

Robert E. Stewart has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Self-calibrating laser semiconductor accelerometer
    Publication number: 20090293583
    Abstract: A self-calibrating laser accelerometer system that continuously removes bias errors from acceleration measurements under dynamic operating conditions has a frame with a pair of essentially identical mass modulated accelerometers positioned within the frame. Each accelerometer includes a proof mass mounted to the sensing element frame by a flexure suspension. The proof mass is arranged to rotate about an output axis in response to acceleration of the sensing element frame along an input axis. The first proof mass includes a secondary mass that is movable between a first stable position on a first side of the output axis and a second stable position on a second side of the output axis to provide mass modulation of the first proof mass and to provide a selectively reversible polarity to the input axis and to provide self-calibration of bias.
    Type: Application
    Filed: May 30, 2008
    Publication date: December 3, 2009
    Inventors: Robert E. Stewart, David B. Hall, A. Douglas Meyer
  • System and method for mitigating errors in electrostatic force balanced instrument
    Patent number: 7614300
    Abstract: System and method for mitigating errors in electrostatic force balanced instrument is provided. The system and method mitigate errors in measurement readings caused by charge buildup in force balanced instruments that employ charge pulses to generate an electrostatic force to null an inertial proof mass disposed between opposing electrodes. The system and method mitigate charge buildup by applying charge pulses to each opposing electrode of a sensing element for a given charge cycle time period in a normal polarity configuration followed by charge pulses to each opposing electrode of the sensing element for a second given charge cycle time period in a reverse polarity configuration.
    Type: Grant
    Filed: May 30, 2007
    Date of Patent: November 10, 2009
    Assignee: Northrop Grumman Corporation
    Inventors: Robert E. Stewart, Robert Griffith
  • Bias and quadrature reduction in class II coriolis vibratory gyros
    Patent number: 7565839
    Abstract: The method and apparartus in one embodiment may have the steps of: providing a two-dimensional axisymmetric oscillator having a beam containing two principal elastic axes and two principal damping axes; driving the beam with drive components to oscillate; driving, during a first period, the beam along a drive axis of the beam in a direction normal to one pair of faces of the beam while Coriolis coupled vibration is sensed along a sense axis of the beam normal to an orthogonal pair of faces of the beam; reversing, during a second period, drive and sense axes driving the beam; reducing a bias of the beam to zero; and reducing a quadrature of the beam to zero.
    Type: Grant
    Filed: August 7, 2006
    Date of Patent: July 28, 2009
    Assignee: Northrop Grumman Guidance and Electronics Company, Inc.
    Inventors: Robert E. Stewart, Stanley F. Wyse
  • Capacitive bulk acoustic wave disk gyroscopes with self-calibration
    Publication number: 20090173157
    Abstract: The apparatus in one embodiment may have capacitive bulk acoustic wave disk gyro operated in a closed loop mode. A self-calibration system may be operatively coupled to the capacitive bulk acoustic wave disk gyroscope. Self-calibration of gyro bias of the gyro may be implemented by interchanging an anti-nodal axis with a nodal axis of the gyro.
    Type: Application
    Filed: January 8, 2008
    Publication date: July 9, 2009
    Inventor: Robert E. Stewart
  • Fastener assembly and method of manufacture
    Patent number: 7527464
    Abstract: A fastener assembly includes a retainer clip having a base, a deck spaced from the base and an opening in the base aligned with the deck. A threaded fastener has a head received through the opening in the base and non-rotatably secured to the deck, and an externally threaded body that extends through the opening in the base.
    Type: Grant
    Filed: February 16, 2005
    Date of Patent: May 5, 2009
    Assignee: Alpha Stamping Company
    Inventors: Robert E. Stewart, Carl L. Lewis
  • Micro hemispheric resonator gyro
    Publication number: 20090031831
    Abstract: One embodiment is a micro hemispheric resonator gyro having: a plurality of pickoff and forcer electrodes; a hemispheric resonator; a guard ring having first and second opposed sides, the guard ring containing the plurality of pickoff and forcer electrodes, and the hemispheric resonator; a top cover operatively coupled to the first side of the guard ring; and a bottom cover operatively coupled to the second side of the guard ring; wherein the plurality of pickoff and forcer electrodes, the hemispheric resonator, the guard ring, the top cover and the bottom cover form a micro hemispheric resonator gyro.
    Type: Application
    Filed: July 31, 2007
    Publication date: February 5, 2009
    Inventor: Robert E. Stewart
  • Self-calibrating nuclear magnetic resonance gyro
    Publication number: 20090033329
    Abstract: The method and apparatus in one embodiment may have: a gyro housing containing a bias field; a bias field that generates a stable axial magnetic field; Xenon or other gas contained within at least a portion of the axial magnetic field, Xenon or other gas nuclear spins precessing at a constant angular rate with respect to the gyro housing in response to the axial magnetic field; wherein reversing a polarity of the bias field reverses a polarity of the magnetic field and a polarity of the precession of the Xenon or other gas nuclear spin, and wherein a reversing of the polarity of the gyro scalefactor thereby results without reversing a polarity of the gyro bias.
    Type: Application
    Filed: July 31, 2007
    Publication date: February 5, 2009
    Inventors: Robert E. Stewart, Edward Kanegsberg
  • System and Method for Mitigating Errors in Electrostatic Force Balanced Instrument
    Publication number: 20080295597
    Abstract: System and method for mitigating errors in electrostatic force balanced instrument is provided. The system and method mitigate errors in measurement readings caused by charge buildup in force balanced instruments that employ charge pulses to generate an electrostatic force to null an inertial proof mass disposed between opposing electrodes. The system and method mitigate charge buildup by applying charge pulses to each opposing electrode of a sensing element for a given charge cycle time period in a normal polarity configuration followed by charge pulses to each opposing electrode of the sensing element for a second given charge cycle time period in a reverse polarity conjuration.
    Type: Application
    Filed: May 30, 2007
    Publication date: December 4, 2008
    Inventors: Robert E. Stewart, Robert Griffith
  • Flexible support for dock fender
    Patent number: 7448338
    Abstract: A dock fender support bracket includes a cup-like holder section having a sidewall and a bottom wall and a pair of axially aligned holes through the sidewall. In one embodiment, the support bracket includes a clevis section having a body with spaced flanges oriented inside of the cup-like holder section and extending in parallel planes. In another embodiment, the support bracket is integrally molded. An elongate section of the support bracket is configured to be attached to a dock and to elastically flex in all directions transverse of a longitudinal axis thereof. The elongate section can be formed of a hollow or solid resin, and can include spring or metal reinforcement. The support bracket is configured to support the dock fender at the cup-like holder section. A resilient insert can support a rod-mounted fender.
    Type: Grant
    Filed: August 15, 2006
    Date of Patent: November 11, 2008
    Assignee: Buoyant Solutions, Inc.
    Inventors: Robert E. Stewart, Daniel F. Stanek
  • RING RESONATOR GYROSCOPE WITH CYLINDRICAL RING SUSPENSION
    Publication number: 20080264168
    Abstract: A ring resonator gyro comprises a cylindrical ring suspension. The cylindrical ring suspension supports a cylindrical ring resonator. The cylindrical ring resonator is coupled with an outer perimeter of the ring suspension.
    Type: Application
    Filed: August 7, 2006
    Publication date: October 30, 2008
    Inventor: Robert E. Stewart
  • Ring resonator gyroscope with cylindrical ring suspension
    Patent number: 7434465
    Abstract: A ring resonator gyro comprises a cylindrical ring suspension. The cylindrical ring suspension supports a cylindrical ring resonator. The cylindrical ring resonator is coupled with an outer perimeter of the ring suspension.
    Type: Grant
    Filed: August 7, 2006
    Date of Patent: October 14, 2008
    Assignee: Litton Systems Inc.
    Inventor: Robert E. Stewart
  • Self-calibrating accelerometer
    Publication number: 20080236242
    Abstract: The method and apparatus in one embodiment may have: a sensing element for an accelerometer having a bias, the sensing element having a rectangular plate supported by flexures which allow rotation about a transverse center line thereof; a center of mass (CG) of the sensing element having two stable positions, one on each side of an axis of rotation defined by a centerline of suspension; a secondary mass within a proofmass translates in-plane to move the center of mass to thereby effect a self-calibration mechanization that continuously measures and nulls the accelerometer's bias under dynamic operating conditions.
    Type: Application
    Filed: March 28, 2007
    Publication date: October 2, 2008
    Inventor: Robert E. Stewart
  • Ring resonator gyro with folded cylinder suspension
    Patent number: 7426860
    Abstract: A ring resonator gyro comprises a folded cylinder suspension that supports a cylindrical ring resonator. The folded cylinder suspension comprises an inner cylinder, an outer cylinder, and an annulus. The inner cylinder, the outer cylinder, and the annulus are concentric. A top edge of the inner cylinder is coupled with an inner edge of the annulus. A top edge of the outer cylinder is coupled with an outer edge of the annulus.
    Type: Grant
    Filed: August 7, 2006
    Date of Patent: September 23, 2008
    Assignee: Litton Systems Inc.
    Inventor: Robert E. Stewart
  • Self-calibration of scale factor for dual resonator class II coriolis vibratory gyros
    Publication number: 20080223107
    Abstract: The method and apparatus in one embodiment may have: operating one of two resonators of a class II coriolis vibratory gyro in a closed loop mode and another of the two resonators in an open loop whole angle mode; sensing an angular rate by each of the two resonators; calibrating the scale factor of the closed loop resonator to yield the same integrated whole angle as measured by the open loop resonator; reversing operation of the two resonators such that the one of two resonators is operated in an open loop mode and the another of the two resonators in a closed loop whole angle mode; and alternately proceeding between open and closed loop operation of the two resonators, thereby self-calibrating scale factors respectively of the two resonators.
    Type: Application
    Filed: March 15, 2007
    Publication date: September 18, 2008
    Inventor: Robert E. Stewart
  • Method for modifying the location of nodal points of a vibrating beam
    Patent number: 7392702
    Abstract: The apparatus in one embodiment may have: a beam having at least first and second mounting points that are operatively coupled to the beam by first and second flexures, respectivly; the beam having first and second nodal points; the beam having a center area; and an altered mass content in a vicinity of the center area, the altered mass content being such that the first and second nodal points are substantially aligned with the first and second flexures. The beam is therefore supported at the nodal points for the fundamental mode of vibration.
    Type: Grant
    Filed: August 7, 2006
    Date of Patent: July 1, 2008
    Assignee: Litton Systems Inc.
    Inventors: Robert E. Stewart, Michae W. Denice, Jr.
  • Flexible support for dock fender
    Publication number: 20080041290
    Abstract: A dock fender support bracket includes a cup-like holder section having a sidewall and a bottom wall and a pair of axially aligned holes through the sidewall. In one embodiment, the support bracket includes a clevis section having a body with spaced flanges oriented inside of the cup-like holder section and extending in parallel planes. In another embodiment, the support bracket is integrally molded. An elongate section of the support bracket is configured to be attached to a dock and to elastically flex in all directions transverse of a longitudinal axis thereof. The elongate section can be formed of a hollow or solid resin, and can include spring or metal reinforcement. The support bracket is configured to support the dock fender at the cup-like holder section. A resilient insert can support a rod-mounted fender.
    Type: Application
    Filed: August 15, 2006
    Publication date: February 21, 2008
    Inventors: Robert E. Stewart, Daniel F. Stanek
  • Support of vibrating beam near nodal point
    Patent number: 7322238
    Abstract: An apparatus in one example comprises a vibrating beam that comprises a nodal point for oscillation in any one or more of a plurality of substantially perpendicular directions for driving into oscillation and sensing angular rate of the vibrating beam. The vibrating beam comprises an aperture that allows a frame to support the vibrating beam near the nodal point.
    Type: Grant
    Filed: February 11, 2005
    Date of Patent: January 29, 2008
    Assignee: Northrop Grumman Corporation
    Inventor: Robert E. Stewart
  • Middle layer of die structure that comprises a cavity that holds an alkali metal
    Patent number: 7292111
    Abstract: An apparatus in one example comprises a die structure that comprises a middle layer, a first outside layer, and a second outside layer. The middle layer comprises a cavity that holds an alkali metal, and one of the first outside layer and the second outside layer comprises a channel that leads to the cavity. The middle layer, the first outside layer, and the second outside layer comprise dies from one or more wafer substrates.
    Type: Grant
    Filed: April 26, 2004
    Date of Patent: November 6, 2007
    Assignee: Northrop Grumman Corporation
    Inventors: Henry C. Abbink, William P. Debley, Christine E. Geosling, Daryl K. Sakaida, Robert E. Stewart
  • Heating element induction of time-varying thermal gradient in elongated beam to cause one or more elongated beam oscillations
    Patent number: 7274002
    Abstract: One or more heating elements comprise a heating element. One or more elongated beams comprise an elongated beam. The heating element is coupled with the elongated beam and induces a time-varying thermal gradient in the elongated beam to cause one or more oscillations of one or more of the one or more elongated beams.
    Type: Grant
    Filed: July 12, 2006
    Date of Patent: September 25, 2007
    Assignee: Northrop Grumman Corporation
    Inventor: Robert E. Stewart
  • Coplanar proofmasses employable to sense acceleration along three axes
    Patent number: 7178398
    Abstract: An apparatus in one example comprises a first proofmass employable to sense a first acceleration along a first input axis; a second proofmass employable to sense a second acceleration along a second input axis; and a third proofmass employable to sense a third acceleration along a third input axis. The first input axis, the second input axis, and the third input axis are substantially orthogonal. The first proofmass, the second proofmass, and the third proofmass are substantially coplanar.
    Type: Grant
    Filed: December 13, 2004
    Date of Patent: February 20, 2007
    Assignee: Northrop Grumman Corporation
    Inventor: Robert E. Stewart