By Motor Torque Patents (Class 74/5.47)
  • Patent number: 11931888
    Abstract: A robotic tool has a longitudinal shaft, defining a longitudinal axis when the shaft is in a default, centered position. A lockout rod is moveable between first and second positions. In the first position, the lockout rod allows the longitudinal shaft to move with 360 radial degrees of compliance about the longitudinal axis. In the second position, the lockout rod limits compliance of the longitudinal shaft to only one radial angle from the longitudinal axis. In one embodiment the lockout rod is positioned adjacent (e.g., above or below) part of one ring of a 2-axis concentric ring gimbal. The lockout rod is shaped so as to not contact any part of the gimbal in the first position, allowing compliance in a full 360 radial degrees. In the second position, the lockout rod limits the motion of one ring of the gimbal, limiting compliance of the shaft to motion of the other ring, which is necessarily limited to only one radial angle.
    Type: Grant
    Filed: November 1, 2019
    Date of Patent: March 19, 2024
    Assignee: ATI Industrial Automation, Inc.
    Inventor: David John Bohle, II
  • Patent number: 10714807
    Abstract: A stabilization arrangement (10) for stabilizing an antenna mast (3), comprising an antenna mast (3) and a gyroscopic stabilizer device (12), wherein the gyroscopic stabilizer device (12) in turn comprises a flywheel (11), a flywheel axis (14), wherein the flywheel (11) is arranged about the flywheel axis (14), and a gimbal structure (13), wherein the flywheel (11) is suspended in the gimbal structure (13) and the gimbal structure (13) is configured to permit flywheel precession or tilting about at least one gimbal output axis (16). The gyroscopic stabilizer device (12) is fixedly arranged in connection to a first end portion (31) of the antenna mast (3) and the antenna mast (3) is fastenable to a supporting structure at a second end portion (32) of the antenna mast (3), wherein the gyroscopic stabilizer device (12) is configured to reduce movements in a plane perpendicular to the extension of the antenna mast (3).
    Type: Grant
    Filed: September 6, 2017
    Date of Patent: July 14, 2020
    Assignee: SAAB AB
    Inventor: Martin Blennius
  • Patent number: 8650976
    Abstract: A gyroscope power starter has a housing having a bottom and a concave head slanted at a predetermined angle relative to the housing, the concave head engaging a gyroscope rotor. An electric power source is mounted on the housing. A motor is rigidly mounted to a housing. The motor is connected to the power source for producing a rotational power in response to a switching force. A power rotor is connected in unity with the motor and protruding from an opening into the concave head of the housing to transmit the rotational motor power to the gyroscope rotor. An alignment member is formed in a concave center area. The alignment member protrudes into a groove of a gyroscopic rotor when the gyroscopic rotor is rotating.
    Type: Grant
    Filed: July 20, 2010
    Date of Patent: February 18, 2014
    Inventor: Tom Smith
  • Patent number: 8210062
    Abstract: An attitude control system for a spacecraft is disclosed that includes a scissored pair of control moment gyroscopes for delivering an output torque to the spacecraft along a an output axis, wherein each gyroscope has a spin motor for spinning a rotor about a rotor axis and a gimbal torque motor for rotating the rotor about a gimbal axis, and wherein the system includes a generator for extracting kinetic energy from the rotors during rotor deceleration to power the gimbal torque motors of the gyroscopes.
    Type: Grant
    Filed: April 18, 2007
    Date of Patent: July 3, 2012
    Assignee: Ithaco Space Systems, Inc.
    Inventors: William Edward Bialke, Eric Stromswold
  • Patent number: 8205514
    Abstract: A control moment gyroscope (CMG) is provided for deployment on a spacecraft. The CMG includes a stator housing, an inner gimbal assembly disposed in the stator housing, and a torque motor coupled to the stator housing and at least partially disposed around an intermediate portion of the inner gimbal assembly. The torque motor is configured to rotate the inner gimbal assembly about a gimbal axis.
    Type: Grant
    Filed: January 18, 2008
    Date of Patent: June 26, 2012
    Assignee: Honeywell International Inc.
    Inventors: Carlos J. Stevens, Stephen E. Fiske
  • Patent number: 8164294
    Abstract: In general, one aspect of the subject matter described in this specification features a torquer apparatus that includes a rotor with magnetic poles such that, when radially projected on a concentric octahedron, the same symmetrical pattern is obtained on all faces of the octahedron, the polarity of the poles projected on two adjacent faces of the octahedron being opposite. A stator with at least twenty poles magnetized with coils and such that, when radially projected on a concentric icosahedron, the same symmetrical pattern is obtained on all faces of the icosahedron, the stator being-in nominal position-concentric with the rotor. Real-time measurements, or equivalent information, of the position of the rotor with respect to the stator, and real-time measurements, or equivalent information, of exported torque from the stator, or of the orientation of the rotor with respect to the stator can be obtained.
    Type: Grant
    Filed: March 28, 2007
    Date of Patent: April 24, 2012
    Inventor: Olivier Chételat
  • Patent number: 8104364
    Abstract: Described is a gyroscope with a vibrating structure, produced by micromachining in a thin wafer, which comprises a movable inertial assembly comprising at least one movable mass able to vibrate in the plane of the wafer along a drive axis x and along a sense axis y roughly perpendicular to the x-axis, an interdigital sensor comb and an interdigital drive comb. It furthermore comprises at least one additional interdigital comb, called the quadrature-error compensation comb, connected to the mass and which has two asymmetric air gaps e and ?e, ? being a positive real number, for subjecting the mass to an adjustable electrostatic stiffness due to coupling between the x-axis and the y-axis by applying a variable DC voltage V to this comb, the adjustable stiffness allowing compensation for the quadrature error of the gyroscope.
    Type: Grant
    Filed: December 7, 2006
    Date of Patent: January 31, 2012
    Assignee: Thales
    Inventor: Bernard Chaumet
  • Patent number: 8061226
    Abstract: A device for use with a gyroscopic stabilizer for use in an assembly that is moveably connected to a vehicle. The gyroscopic stabilizer has a gyroscope, a skew motor, and a skew motor velocity servo-control system. The gyroscopic stabilizer can control a skew of the assembly based on a torque signal to maintain the assembly in an intended position. The skew motor velocity servo-control system can control the skew motor. The skew motor can move the gyroscope. The gyroscope can provide the torque signal. The device comprises an assembly position determining system, a detector, a state estimator and an output portion. The assembly position determining system can generate an assembly position signal based on one of a position of the assembly, a position of the gyroscopic stabilizer, a position of the gyroscope, a position of the skew motor and a position of the skew motor velocity servo-control system.
    Type: Grant
    Filed: June 2, 2008
    Date of Patent: November 22, 2011
    Assignee: KVH Industries, Inc.
    Inventor: Ahmed Zaki
  • Patent number: 8047090
    Abstract: The present invention relates to motors and, more specifically to rotary motors which can supply output motive power about an output axis in response to input rotary power about a different axis. A motor (1) comprises a wheel (2) mounted on a shaft (3) for rotation about a first axis (4). The shaft (3) is additionally mounted for rotation about both an inclination axis (16) and the output axis (11) of the motor (1).
    Type: Grant
    Filed: November 13, 2006
    Date of Patent: November 1, 2011
    Assignee: Erke Erke Arastirmalari Ve Muhendislik A.S.
    Inventor: Mustafa Naci Öztürk
  • Patent number: 8020809
    Abstract: A control moment gyroscope system for delivering a target torque to a spacecraft including a rotor assembly having a rotor and a motor to spin the rotor about a rotor axis. A gimbal assembly has a gimbal for supporting the rotor assembly and a gimbal torque motor to rotate the gimbal about a gimbal axis, which is normal to the rotor axis, to generate an output torque. A control system has a sensor for determining the output torque and a processor in communication with the rotor assembly, the gimbal assembly and the sensor. The processor requests the target torque and establishes a feedback control loop to generate a torque error signal based on the output torque for bringing the output torque within a predetermined range of the target torque.
    Type: Grant
    Filed: April 18, 2008
    Date of Patent: September 20, 2011
    Assignee: Ithaco Space Systems, Inc.
    Inventors: Mason Peck, William E. Bialke
  • Patent number: 7997157
    Abstract: A control moment gyroscope (CMG) is provided for deployment on a spacecraft. The CMG includes an inner gimbal assembly (IGA), which, in turn, includes an IGA housing, a rotor rotatably coupled to the IGA housing, and a spin motor coupled to the IGA housing and configured to rotate the rotor about a spin axis. The CMG further comprises a stator assembly, which includes: (i) a stator assembly housing rotatably coupled to the IGA housing, and (ii) a torque module assembly coupled to the stator assembly housing and configured to rotate the IGA about a gimbal axis. A gimbal bearing is disposed between the IGA housing and the stator assembly housing. The gimbal bearing resides between the spin axis and the torque module assembly such that the distance between the gimbal bearing and the spin axis is less than the distance between the gimbal bearing and the torque module assembly.
    Type: Grant
    Filed: February 11, 2008
    Date of Patent: August 16, 2011
    Assignee: Honeywell International Inc.
    Inventors: Dennis Wayne Smith, Paul Buchele, Carlos J. Stevens, Stephen Edward Fiske
  • Publication number: 20110041628
    Abstract: The invention concerns a gear device, preferably motor device, for providing rotation about at least one output axis and a method for providing rotation. A body (2) is mounted for a rotation about first (4), second (11), and third (16) axes. The first axis (4) is oriented with respect to the second axis (11) at an inclination angle. The second axis (11) and/or the third axis (16) constitute the at least one output axis of device. The rotation of the body (2) about the third axis (16) gives rise to a change in the inclination angle. A ram (15) applies a torque (21) to the body (2) about the third axis (16) in a sense of increasing inclination angle when the first axis (4) is at a selected inclination angle with respect to the second axis (11) which is greater than 0° and less than 90°.
    Type: Application
    Filed: April 17, 2008
    Publication date: February 24, 2011
    Applicant: ERKE ERKE ARASTIRMALARI VE MÓHENDISLIK A.S.
    Inventor: Mustafa Naci Ozturk
  • Patent number: 7801657
    Abstract: A control system for a vehicle having first and second wheels is provided that includes a differential apparatus adapted to distribute torque between the first and second wheels and a traction controller for controlling operation of the differential apparatus from vehicle launch up to a predetermined vehicle speed. The traction controller is configured to engage the differential apparatus in a first operating state according to at least one vehicle operating parameter indicative of a low traction operating condition and to further control engagement of the differential apparatus in a second vehicle operating state during the low traction operating condition according to a difference between an actual vehicle yaw rate and a predetermined target vehicle yaw rate. The control system also includes a stability controller for controlling engagement of the differential apparatus at or above the predetermined vehicle speed.
    Type: Grant
    Filed: February 2, 2007
    Date of Patent: September 21, 2010
    Assignee: Eaton Corporation
    Inventors: Damrongrit Piyabongkarn, Jae Y. Lew, John A. Grogg, Robert J. Kyle
  • Patent number: 7698041
    Abstract: A drive unit includes an engine and a transmission having a variable transmission ratio. An instantaneous setpoint power output quantity of the drive unit is determined from an intended power output. The setpoint power output quantity is a function of the instantaneous transmission ratio of the transmission at least for a given intended power output.
    Type: Grant
    Filed: June 29, 2005
    Date of Patent: April 13, 2010
    Assignee: Robert Bosch GmbH
    Inventor: Martin Streib
  • Publication number: 20090235765
    Abstract: A signal torque module assembly (STMA) is provided for use within a control moment gyroscope of the type that includes a rotor assembly. The STMA comprises a torque module assembly (TMA), which includes: (i) a TMA housing, (ii) a torque motor coupled to the TMA housing, and (iii) a gear train coupled to the TMA housing and mechanically coupling the torque motor to the rotor assembly. A signal module assembly is coupled to the TMA housing, and an elongated connector electrically couples the signal module assembly and the rotor assembly. The elongated connector extends through the gear train.
    Type: Application
    Filed: March 19, 2008
    Publication date: September 24, 2009
    Applicant: Honeywell International Inc.
    Inventors: Paul Buchele, Torey Davis
  • Patent number: 7451667
    Abstract: A precessional device having independent control of the output torque generated by the device and the oscillation rate of the device is disclosed. The device comprises a rotor supported by an axle wherein the ends of the axle are supported by a circular race. The circular race is rotatable, and may be driven by a motor or other means, thereby controlling the oscillation rate of the device independently of the output torque arising from the rotation rate of the rotor. The motor may be controlled by a control program that adjusts the rotation rate of the circular race to modify the shape of the resistance curve.
    Type: Grant
    Filed: October 14, 2006
    Date of Patent: November 18, 2008
    Inventor: Peter Winston Hamady
  • Patent number: 7437961
    Abstract: A power starting dock for gyroscope is comprised of an outer housing that has a bottom and a concave head. The head is slanted at an angle relative to the housing, and engages a gyroscope rotor, an electric power source on the housing, a spring-mounted motor on the housing connected to the power source for producing a rotational power in response to a switching force, and a power rotor fastened to the motor and protruding into the concave head of the housing. The power rotor serves to resiliently transmit rotational motor power to the gyroscope rotor.
    Type: Grant
    Filed: May 16, 2006
    Date of Patent: October 21, 2008
    Assignee: Dynaflex International
    Inventor: Bill Dworzan
  • Patent number: 7437224
    Abstract: A method and apparatus for controlling a gimbaled platform (108). The method comprises the steps of computing an acquisition phase gimbal angle rate command ?cmd—Acq (530) from a measured LOS angle error ??LOS (520) for an initial control period T while computing an estimated LOS angle rate {circumflex over (?)}LOS (524), computing a tracking phase gimbal angle rate command ?cmd—Trk (532) using a controller (512) having an output initialized with the estimated LOS angle rate {circumflex over (?)}LOS (524), and commanding the gimballed platform (108) according to an angle rate command ?cmd (522), wherein the angle rate command ?cmd (522) is the acquisition phase angle rate command ?cmd—Acq (530) during the initial control period T and the tracking phase gimbal angle rate command ?cmd—Trk (532) after the initial control period T.
    Type: Grant
    Filed: September 28, 2004
    Date of Patent: October 14, 2008
    Assignee: The Boeing Company
    Inventors: Tung-Ching Tsao, Ketao Liu
  • Patent number: 7249531
    Abstract: A control moment gyro comprising a wheel support structure which is mounted on a base by a motor, which is used to rotate the support around a first axis and bearing a wheel arrangement for driving the wheel spinner at a high speed around a second axis perpendicuIar to the first. The support structure includes a tubular part which rotates on the base and a flange which is disposed on only one side of the wheel and which is fixed both to the wheel and the tubular part. The diameter of the wheel and the point at which the wheel is fixed to the flange are proportioned such that the wheel penetrates the tubular part.
    Type: Grant
    Filed: March 18, 2003
    Date of Patent: July 31, 2007
    Assignee: Eads Astrium SAS
    Inventors: Ange Defendini, Pascal Guay, Philippe Faucheux
  • Patent number: 7190097
    Abstract: An apparatus for the control and alignment of a sensor on a moving vehicle is provided that includes a gimbal ball supported by an outer axis structure and adapted to pivot about an outer elevation axis and about an outer azimuth axis. The outer axis structure is mounted to a vehicle. An inner axis structure includes a cardan shaft that is provided in the ball and is used to support a payload. An inner elevation axis passes through the cardan shaft. The payload is moved about inner pitch inner roll and inner yaw axes over a limited range of motion by the use of a plurality of permanent magnet wide-gap motors that are disposed on the plane of the cardan shaft and maximally away from the yaw axis in the ball. The motors are adapted to each urge the payload to move in two perpendicular axes, depending upon the current that is applied through conductors which pass through a flux field. Control circuitry is used to energize the motors in any desired combination to produce motion in roll, pitch, or yaw.
    Type: Grant
    Filed: December 15, 2004
    Date of Patent: March 13, 2007
    Inventors: Che Ram Souza Voigt, Allan Alfred Voigt, John Mark Speicher, Chet Alister Johnston
  • Patent number: 7159479
    Abstract: An active damping method for a stabilized mirror, and a corresponding active damper apparatus, comprising providing a tachometer measuring speed of a motor driving the mirror, employing compensation electronics receiving input from said tachometer and the motor, and employing drive electronics providing output to the motor.
    Type: Grant
    Filed: September 25, 2003
    Date of Patent: January 9, 2007
    Assignee: Lockheed Martin Corporation
    Inventor: John G. Hughes
  • Patent number: 7152495
    Abstract: A disturbance-cancellation system and method is provided that facilitates the adaptive cancellation of periodic disturbances. The disturbance-cancellation system and method includes a pair of control moment gyroscopes (CMGs) arranged together as a scissored pair. The scissored pair of CMGs is used to create a periodic torque with a controllable amplitude and frequency. The periodic torque created by the CMGs is adaptively controlled to cancel out periodic disturbances in the system. The system and method creates a periodic torque with a controllable amplitude and frequency by rotating the inner-gimbal assemblies of the CMGs in opposite directions at substantially equal phase and angular velocity. Amplitude matching can be achieved by adjusting the rotor spin rate. The steady-state constant motion results in a periodic torque along the output axis of the scissored pair, while components of torque along axes orthogonal to this one cancel out.
    Type: Grant
    Filed: December 19, 2002
    Date of Patent: December 26, 2006
    Assignee: Honeywell International, Inc.
    Inventor: Mason A. Peck
  • Patent number: 6973847
    Abstract: A gyroscopic roll stabilizer for a boat. The stabilizer includes a flywheel, a flywheel drive motor configured to spin the flywheel about a spin axis, an enclosure surrounding a portion or all of the flywheel and maintaining a below-ambient pressure or containing a below-ambient density gas, a gimbal structure configured to permit flywheel precession about a gimbal axis, and a device for applying a torque to the flywheel about the gimbal axis. The flywheel, enclosure, and gimbal structure are configured so that when installed in the boat the stabilizer damps roll motion of the boat. Preferably, the flywheel drive motor spins the flywheel at high tip speeds.
    Type: Grant
    Filed: June 4, 2003
    Date of Patent: December 13, 2005
    Assignee: Gearloose Engineering, Inc.
    Inventors: John D. Adams, Shepard W. McKenney
  • Patent number: 6860166
    Abstract: A gyroscopic device includes a drive gimbal drive ring spinning about a drive gimbal axis, a precession gimbal spinning about a precession gimbal axis substantially perpendicular to the drive gimbal drive ring, and a gyro coupled to the drive gimbal drive ring rotating about the precession gimbal axis and spinning about a moving gyro spin axis substantially parallel to the drive gimbal ring. The gyro rotation and spin generates a precession force about the drive gimbal axis that is either opposite or coincident the direction of the drive gimbal spin when the depending upon the direction of the gyro. The precession force can be used to propel an object.
    Type: Grant
    Filed: December 3, 2002
    Date of Patent: March 1, 2005
    Inventor: Nathaniel Joseph Hintz
  • Patent number: 6849980
    Abstract: An apparatus for the control and alignment of a sensor on a moving vehicle is provided that includes a gimbal ball supported by an outer axis structure and adapted to pivot about an outer elevation axis and about an outer azimuth axis. The outer axis structure is mounted to a vehicle. An inner axis structure includes a cardan shaft that is provided in the ball and is used to support a payload. An inner elevation axis passes through the cardan shaft. The payload is moved about inner pitch inner roll and inner yaw axes over a limited range of motion by the use of a plurality of permanent magnet wide-gap motors that are disposed on the plane of the cardan shaft and maximally away from the yaw axis in the ball. The motors are adapted to each urge the payload to move in two perpendicular axes, depending upon the current that is applied through conductors which pass through a flux field. Control circuitry is used to energize the motors in any desired combination to produce motion in roll, pitch, or yaw.
    Type: Grant
    Filed: February 21, 2003
    Date of Patent: February 1, 2005
    Inventors: Che Ram Souza Voigt, Allan Alfred Voigt, John Mark Speicher, Chet Alister Johnston
  • Publication number: 20040244513
    Abstract: A gyroscopic roll stabilizer for a boat. The stabilizer includes a flywheel, a flywheel drive motor configured to spin the flywheel about a spin axis, an enclosure surrounding a portion or all of the flywheel and maintaining a below-ambient pressure or containing a below-ambient density gas, a gimbal structure configured to permit flywheel precession about a gimbal axis, and a device for applying a torque to the flywheel about the gimbal axis. The flywheel, enclosure, and gimbal structure are configured so that when installed in the boat the stabilizer damps roll motion of the boat. Preferably, the flywheel drive motor spins the flywheel at high tip speeds.
    Type: Application
    Filed: June 4, 2003
    Publication date: December 9, 2004
    Inventors: John D. Adams, Shepard W. McKenney
  • Patent number: 6789437
    Abstract: An apparatus and a method for controlling the path of oscillatory travel of a device within a two-axis system. A device, such as a camera, is held in a two axis gimbal system having motors for driving the azimuth and pitch axes. A two degree-of-freedom gyroscope is fixed to the case of the device. A first derivative circuit is interposed between a first input port for a loop for controlling device movement with respect to a first axis and a second input port for a loop for controlling device movement with respect to a second axis. Likewise, a second derivative circuit is interposed between the two input ports so that a periodic signal driving with respect to one axis generates a derivative function for driving with respect to the cross-axis. The cross axis signal is scaled to counteract the direct torquing of the gyro rotor that otherwise prevents smooth oscillatory slewing or scanning by the device.
    Type: Grant
    Filed: July 31, 2001
    Date of Patent: September 14, 2004
    Assignee: Northrop Grumman Systems Corporation
    Inventor: Stanley F. Wyse
  • Publication number: 20040103728
    Abstract: A gyroscopic device includes a drive gimbal drive ring spinning about a drive gimbal axis, a precession gimbal spinning about a precession gimbal axis substantially perpendicular to the drive gimbal drive ring, and a gyro coupled to the drive gimbal drive ring rotating about the precession gimbal axis and spinning about a moving gyro spin axis substantially parallel to the drive gimbal ring. The gyro rotation and spin generates a precession force about the drive gimbal axis that is either opposite or coincident the direction of the drive gimbal spin when the depending upon the direction of the gyro. The precession force can be used to propel an object.
    Type: Application
    Filed: December 3, 2002
    Publication date: June 3, 2004
    Inventor: Nathaniel Joseph Hintz
  • Publication number: 20040035229
    Abstract: The present invention provides a control moment gyroscope that overcomes many of the limitations of the prior art. The control moment gyroscope provides a radial actuator mechanism to provide rotation to an inner gimbal assembly around a gimbal axis. The radial actuator mechanism comprises a circular ring at the midpoint of the gimbal axis, the circular ring extending around the outer periphery of the inner gimbal assembly housing. The radial actuator mechanism rotates the inner gimbal assembly around the gimbal axis through the use of a non-contact motor that provides rotational force directly to the outer perimeter of the inner gimbal assembly. Because the inner gimbal assembly is rotated from the midpoint of the gimbal axis, a torque module assembly at the end of the gimbal axis is not required. Thus, the overall length of the control moment gyroscope can be reduced.
    Type: Application
    Filed: August 22, 2002
    Publication date: February 26, 2004
    Inventor: Marc E. Meffe
  • Patent number: 6681649
    Abstract: An inertial control and measurement system is provided for applying inertial control to a vehicle and measuring angular rate of the vehicle. The system includes a control moment gyroscope having a spinning rotor, a gimbal, a gimbal support assembly attached to a spacecraft for allowing rotation of the gimbal about a gimbal axis, and a gimbal motor for rotating the gimbal about the gimbal axis to induce torque. A controller controls the gimbal motor to generate a control torque. The controller further determines an angular rate of the vehicle as a function of a determined torque and a gimbal angle acceleration.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: January 27, 2004
    Assignee: Honeywell International Inc.
    Inventors: Tristram T. Hyde, Lawrence P. Davis
  • Publication number: 20030188592
    Abstract: An inertial control and measurement system is provided for applying inertial control to a vehicle and measuring angular rate of the vehicle. The system includes a control moment gyroscope having a spinning rotor, a gimbal, a gimbal support assembly attached to a spacecraft for allowing rotation of the gimbal about a gimbal axis, and a gimbal motor for rotating the gimbal about the gimbal axis to induce torque. A controller controls the gimbal motor to generate a control torque. The controller further determines an angular rate of the vehicle as a function of a determined torque and a gimbal angle acceleration.
    Type: Application
    Filed: April 3, 2002
    Publication date: October 9, 2003
    Inventors: Tristram T. Hyde, Lawrence P. Davis
  • Patent number: 6354163
    Abstract: In a CMG array used to change the attitude of a satellite, noise in the motion of the inner gimbal as it is moved is detected and the speed of the CMG rotors is changed to reduce the noise.
    Type: Grant
    Filed: May 17, 2000
    Date of Patent: March 12, 2002
    Assignee: Honeywell International Inc.
    Inventor: Christopher J. Heiberg