Patents by Inventor Dean C. Alhorn

Dean C. Alhorn 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).

  • Patent number: 9825641
    Abstract: A reconfigurable sensor monitoring system includes software tunable filters, each of which is programmable to condition one type of analog signal. A processor coupled to the software tunable filters receives each type of analog signal so-conditioned.
    Type: Grant
    Filed: September 12, 2014
    Date of Patent: November 21, 2017
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Dean C. Alhorn, Kenneth R. Dutton, David E. Howard, Dennis A. Smith
  • Patent number: 9632491
    Abstract: A reconfigurable drive current system includes drive stages, each of which includes a high-side transistor and a low-side transistor in a totem pole configuration. A current monitor is coupled to an output of each drive stage. Input channels are provided to receive input signals. A processor is coupled to the input channels and to each current monitor for generating at least one drive signal using at least one of the input signals and current measured by at least one of the current monitors. A pulse width modulation generator is coupled to the processor and each drive stage for varying the drive signals as a function of time prior to being supplied to at least one of the drive stages.
    Type: Grant
    Filed: June 18, 2014
    Date of Patent: April 25, 2017
    Assignee: The United States of America as Represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Dean C. Alhorn, Kenneth R. Dutton, David E. Howard, Dennis A. Smith
  • Patent number: 8290435
    Abstract: A short-range communication system includes an antenna, a transmitter, and a receiver. The antenna is an electrical conductor formed as a planar coil with rings thereof being uniformly spaced. The transmitter is spaced apart from the plane of the coil by a gap. An amplitude-modulated and asynchronous signal indicative of a data stream of known peak amplitude is transmitted into the gap. The receiver detects the coil's resonance and decodes same to recover the data stream.
    Type: Grant
    Filed: September 30, 2008
    Date of Patent: October 16, 2012
    Assignee: The United States of America as Represented by the Administrator of the Administrator of the National Aeronautics and Space Administration
    Inventors: Dean C. Alhorn, David E. Howard, Dennis A. Smith
  • Patent number: 8098060
    Abstract: Systems, methods and apparatus are provided through which in some implementations determine the amplitude of an amplitude modulated signal, modulated by the position of an object being sensed. In some aspects, the apparatus accepts an excitation signal and the amplitude modulated signal and divides the amplitude modulated by the excitation signal to produce an output signal that is proportional to the position of the object being sensed. In other aspects, the division is performed only when the excitation signal is non-zero, such as close to the peaks in the excitation signal. In other aspects, the excitation signal and amplitude modulated signal are degraded due to an air gap and the degraded signals are used to correct for amplitude fluctuations due to the air gap, and produce an output signal, tolerant of the air gaps, that is proportional to the position of the object being sensed.
    Type: Grant
    Filed: July 15, 2008
    Date of Patent: January 17, 2012
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: David E. Howard, Dean C. Alhorn, Dennis A. Smith, Kenneth R. Dutton
  • Patent number: 7911174
    Abstract: A method and system are provided for sensing the position of a rotor in a hybrid stepper motor. First and second Hall sensors are positioned in a spaced-apart relationship with the first and second armatures of the rotor such that the first and second Hall sensors generate electrical outputs that are 90° out of phase with one another as the rotor rotates. The electrical outputs are adjusted relative to a reference, and the amplitude of the electrical outputs is further adjusted to account for spacing differences between the rotor and each of the first and second Hall sensors.
    Type: Grant
    Filed: February 28, 2008
    Date of Patent: March 22, 2011
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: David E. Howard, Dean C. Alhorn, Dennis A. Smith
  • Patent number: 7134885
    Abstract: A miniature assembly is disclosed which includes a housing assembly with a cover configured to be sealably secured to a box-like receptacle. The receptacle comprises openings on opposing sides for the seating therein of communications connectors. Enclosed within housing is custom-sized circuit board for supporting, at least, a standard communications interface and at least one electronic device.
    Type: Grant
    Filed: July 20, 2005
    Date of Patent: November 14, 2006
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: David E. Howard, Dennis A. Smith, Dean C. Alhorn
  • Patent number: 7116098
    Abstract: A limit and position sensing system includes a sensor assembly and an emitter. The sensor assembly includes first and second electrical conductors arranged in opposing parallel planes. The first electrical conductor is coiled outwardly from either end thereof in a clockwise fashion to form a first coil region and a second coil region. The second electrical conductor forms a single coil with portions of the single coil's rings lying between the first end and second end of the first electrical conductor being parallel to an axis of the first electrical conductor's plane. Ferromagnetic material is aligned with the first and second electrical conductors and spans beyond (a) the first and second ends of the first electrical conductor, and (b) the portions of the rings of the second electrical conductor's single coil that lie between the first end and second end of the first electrical conductor.
    Type: Grant
    Filed: February 16, 2006
    Date of Patent: October 3, 2006
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Dean C. Alhorn, David E. Howard, Dennis A. Smith
  • Patent number: 7081730
    Abstract: A motor controller system uses a rotary sensor with a plurality of signal conditioning units, coupled to the rotary sensor. Each of these units, which is associated with a particular range of motor output shaft rotation rates, generate a feedback signal indicative of the position of the motor's output shaft. A controller (i) converts a selected motor output shaft rotation rate to a corresponding incremental amount of rotational movement for a selected fixed time period, (ii) selects, at periodic completions of the selected fixed time period, the feedback signal from one of the signal conditioning units for which the particular range of motor output shaft rotation rates associated therewith encompasses the selected motor output shaft rotation rate, and (iii) generates a motor drive signal based on a difference between the incremental amount of rotational movement and the feedback signal from the selected one of the signal conditioning units.
    Type: Grant
    Filed: May 21, 2004
    Date of Patent: July 25, 2006
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: David E. Howard, Dean C. Alhorn, Dennis A. Smith, Kenneth R. Dutton, Mitchell Scott Paulson
  • Patent number: 6313624
    Abstract: A position sensor, such as a rotary position sensor, includes the signal-conditioning electronics in the housing. The signal-conditioning electronics are disposed on a printed wiring board, which is assembled with another printed wiring board including the sensor windings to provide a sub-assembly. A mu-metal shield is interposed between the printed wiring boards to prevent magnetic interference. The sub-assembly is disposed in the sensor housing adjacent to an inductor board which turns on a shaft. The inductor board emanates an internally or externally generated excitation signal that induces a signal in the sensor windings. The induced signal represents the rotary position of the inductor board relative to the sensor winding board.
    Type: Grant
    Filed: November 27, 1998
    Date of Patent: November 6, 2001
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Dean C. Alhorn, David E. Howard, Dennis A. Smith
  • Patent number: 6246228
    Abstract: A position sensor or controller generates a response signal in existing armature windings of an actuator and detects the response signal to determine the position of the armature. To generate the response signal, the actuator includes a sensor excitation winding near the armature. Two sensor excitation windings can be provided, above and below the armature, to cancel out z components and thus allow for a variable gap. The sensor excitation winding or windings are supplied with an excitation signal to induce the response signal in the armature windings. The response signal is derived by differentially amplifying and frequency filtering a raw output of the armature windings. The response signal is demodulated to determine position. If a position controller rather than a mere sensor is desired, the position signal can be buffered, PID compensated, amplified, and fed back to the armature windings.
    Type: Grant
    Filed: November 27, 1998
    Date of Patent: June 12, 2001
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Dean C. Alhorn, David E. Howard
  • Patent number: 6138131
    Abstract: A device suitable for determining arc-tangent of an angle .theta. is provided. Circuitry generates a first square wave at a frequency .omega.t and a second square wave at the frequency .omega.t but shifted by a phase difference equal to the angle .theta.. A pulse width modulation signal generator processes the first and second square waves to generate a pulse width modulation signal having a frequency of .omega.t and having a pulse width that is a function of the phase difference .theta.. The pulse width modulation signal is converted to a DC voltage that is a linear representation of the phase difference .theta..
    Type: Grant
    Filed: November 27, 1998
    Date of Patent: October 24, 2000
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Dean C. Alhorn, David E. Howard, Dennis A. Smith
  • Patent number: 6104328
    Abstract: The converter produces a linear analog signal that is linearly proportional to a shaft angle of a resolver over 360.degree.. An excitation cosine signal supplied to the resolver and a response cosine signal received from the output windings of the resolver are converted to logic level signals. Digital logic is performed on the logic level signals in a programmable digital logic device to produce a logic level pulse-width modulated signal. The logic level pulse-width modulated signal is used to control a switch to switch between two reference voltage levels to produce a pulse-width modulated signal, which is filtered and buffered to produce the linear analog signal.
    Type: Grant
    Filed: November 27, 1998
    Date of Patent: August 15, 2000
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Dean C. Alhorn, David E. Howard, Dennis A. Smith
  • Patent number: 5531093
    Abstract: A method for positioning a scanning instrument to point toward the center of the desired scan wherein the scan is achieved by rotating unbalanced masses (RUMs) rotating about fixed axes of rotation relative to and associated with the instrument, the RUMs being supported on drive shafts spaced from the center of the mass of the instrument and rotating 180 degrees out-of-phase with each other and in planes parallel to each other to achieve the scan. The elevation and cross-elevation angles of the instrument are sensed to determine any offset and offset time rate-of-change and the magnitude and direction are converted to a RUM cycle angular velocity component to be superimposed on the nominal velocity of the RUMs. This RUM angular velocity component modulates the RUM angular velocity to cause the speed of the RUMs to increase and decrease during each revolution to drive the instrument toward the desired center of the scan.
    Type: Grant
    Filed: April 17, 1995
    Date of Patent: July 2, 1996
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Michael E. Polites, Dean C. Alhorn
  • Patent number: 5451945
    Abstract: A multiphase converter circuit generates a plurality of sinusoidal outputs of displaced phase and given speed value from the output of an angular resolver system attachable to a motor excited by these multi-phase outputs, the resolver system having a lower speed value than that of the motor. The angular resolver system provides in parallel format sequential digital numbers indicative of the amount of rotation of the shaft of an angular position sensor associated with the angular resolver system. These numbers are used to excite simultaneously identical addresses of a plurality of addressable memory systems, each memory system having stored therein at sequential addresses sequential values of a sinusoidal wavetrain of a given number of sinusoids. The stored wavetrain values represent sinusoids displaced from each other in phase according to the number of output phases desired.
    Type: Grant
    Filed: February 22, 1994
    Date of Patent: September 19, 1995
    Assignee: The United States of America as represented by the Administrator, National Aeronautics and Space Administration
    Inventors: Dean C. Alhorn, David E. Howard
  • Patent number: 5443247
    Abstract: In a torsion spring the spring action is a result of the relationships between the torque applied in twisting the spring, the angle through which the torsion spring twists, and the modulus of elasticity of the spring material in shear. Torsion springs employed industrially have been strips, rods, or bars, generally termed shafts, capable of being flexed by twisting about their axes. They rely on the variations in shearing forces to furnish an internal restoring torque. In the torsion springs herein the restoring torque is external, and therefore independent of the shearing modulus of elasticity the torsion spring shaft. Also provided herein is a variable stiffness torsion spring. This torsion spring can be so adjusted as to have a given spring constant. Such variable stiffness torsion springs are extremely useful in gimballed payloads such as sensors, telescopes and electronic devices on such platforms as a space shuttle, a space station.
    Type: Grant
    Filed: May 20, 1994
    Date of Patent: August 22, 1995
    Assignee: The United States of America as represented by the Administrator, National Aeronautics and Space Administration
    Inventors: Michael E. Polites, Dean C. Alhorn
  • Patent number: 5396815
    Abstract: Gimballed scanning devices are an important aspect of space science. To achieve a scan pattern some means must be provided which impart to the devices an oscillatory motion. Various forms of machines have been employed for controllably conferring scan patterns on these scanning devices. Although they have included control moment gyroscopes, reaction wheels, torque motors, reaction control systems, and the like, rotating unbalanced mass (RUM) devices are a new and more efficient way to generate scans in gimballed devices or payloads. But they require power consuming and frequently complex auxiliary control systems to position and reposition the particular scan pattern relative to a target or a number of targets. Herein the control system is simplified. In the suspension system provided for payloads rotatably supported in gimbals payload rotation is restricted by a flex pivot so that the payload oscillates, moving in a scan pattern.
    Type: Grant
    Filed: September 15, 1993
    Date of Patent: March 14, 1995
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Michael E. Polites, Dean C. Alhorn