Patents by Inventor Christopher Eric Barnhart

Christopher Eric Barnhart 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).

  • Publication number: 20170143516
    Abstract: In some embodiments of a prosthetic or orthotic ankle/foot, a prediction is made of what the walking speed will be during an upcoming step. When the predicted walking speed is slow, the characteristics of the apparatus are then modified so that less net-work that is performed during that step (as compared to when the predicted walking speed is fast). This may be implemented using one sensor from which the walking speed can be predicted, and a second sensor from which ankle torque can be determined. A controller receives inputs from those sensors, and controls a motor's torque so that the torque for slow walking speeds is lower than the torque for fast walking speeds. This reduces the work performed by the actuator over a gait cycle and the peak actuator power delivered during the gait cycle.
    Type: Application
    Filed: December 13, 2016
    Publication date: May 25, 2017
    Inventors: HUGH MILLER HERR, RICHARD J. CASLER, ZHIXIU HAN, CHRISTOPHER ERIC BARNHART, GARY GIRZON
  • Publication number: 20150127118
    Abstract: A time-dependent decay behavior is incorporated into one or more joint actuator control parameters during operation of a lower-extremity, prosthetic, orthotic or exoskeleton device. These parameters may include joint equilibrium joint impedance (e.g., stiffness, damping) and/or joint torque components (e.g., gain, exponent). The decay behavior may be exponential, linear, piecewise, or may conform to any other suitable function. Embodiments presented herein are used in a control system that emulates biological muscle-tendon reflex response providing for a natural walking experience. Further, joint impedance may depend on an angular rate of the joint. Such a relationship between angular rate and joint impedance may assist a wearer in carrying out certain activities, such as standing up and ascending a ladder.
    Type: Application
    Filed: June 12, 2013
    Publication date: May 7, 2015
    Applicant: iWalk, Inc.
    Inventors: Hugh Miller Herr, Zhixiu Han, Christopher Eric Barnhart, Richard J. Casler, JR.
  • Publication number: 20140296997
    Abstract: In an artificial limb system having an actuator coupled to a joint for applying a torque characteristic thereto, a control bandwidth of a motor controller for a motor included in the actuator can be increased by augmenting a current feedback loop in the motor controller with a feed forward of estimated back electromotive force (emf) voltage associated with, the motor. Alternatively, the current loop is eliminated and replaced with a voltage loop related to joint torque. The voltage loop may also be augmented with the feed forward of estimated back emf, to improve the robustness of the motor controller.
    Type: Application
    Filed: November 2, 2012
    Publication date: October 2, 2014
    Applicant: iWalk, Inc.
    Inventors: Hugh Miller Herr, Christopher Williams, Christopher Eric Barnhart, Zhixiu Han, Charles E. Rohrs, Richard J. Casler, JR.
  • Publication number: 20140121782
    Abstract: In some embodiments of a prosthetic or orthotic ankle/foot, a prediction is made of what the walking speed will be during an upcoming step. When the predicted walking speed is slow, the characteristics of the apparatus are then modified so that less net-work that is performed during that step (as compared to when the predicted walking speed is fast). This may be implemented using one sensor from which the walking speed can be predicted, and a second sensor from which ankle torque can be determined. A controller receives inputs from those sensors, and controls a motor's torque so that the torque for slow walking speeds is lower than the torque for fast walking speeds. This reduces the work performed by the actuator over a gait cycle and the peak actuator power delivered during the gait cycle.
    Type: Application
    Filed: January 9, 2014
    Publication date: May 1, 2014
    Applicant: iWalk, Inc.
    Inventors: Hugh Miller Herr, Richard J. Casler, JR., Zhixiu Han, Christopher Eric Barnhart, Gary Girzon, David Adams Garlow
  • Publication number: 20140114437
    Abstract: In some embodiments of a prosthetic or orthotic ankle/foot, a prediction is made of what the walking speed will be during an upcoming step. When the predicted walking speed is slow, the characteristics of the apparatus are then modified so that less net-work that is performed during that step (as compared to when the predicted walking speed is fast). This may be implemented using one sensor from which the walking speed can be predicted, and a second sensor from which ankle torque can be determined. A controller receives inputs from those sensors, and controls a motor's torque so that the torque for slow walking speeds is lower than the torque for fast walking speeds. This reduces the work performed by the actuator over a gait cycle and the peak actuator power delivered during the gait cycle.
    Type: Application
    Filed: December 20, 2013
    Publication date: April 24, 2014
    Applicant: iWalk, Inc.
    Inventors: Hugh Miller Herr, Richard J. Casler, JR., Zhixiu Han, Christopher Eric Barnhart, Gary Girzon
  • Publication number: 20140088727
    Abstract: In a communication system for controlling a powered human augmentation device, a parameter of the powered device is adjusted within a gait cycle by wirelessly transmitting a control signal thereto, whereby the adjusted parameter falls within a target range corresponding to that parameter. The target range is selected and the device parameters are controlled such that the powered device can normalize or augment human biomechanical function, responsive to a wearer's activity, regardless of speed and terrain and, in effect, provides at least a biomimetic response to the wearer of the powered device.
    Type: Application
    Filed: November 26, 2013
    Publication date: March 27, 2014
    Applicant: iWalk, Inc.
    Inventors: Zhixiu Han, Christopher Eric Barnhart, David Adams Garlow, Adrienne Bolger, Hugh Miller Herr, Gary Girzon, Richard J. Casler, JR., Jennifer T. McCarthy