Patents by Inventor Lisa A. Obermaier

Lisa A. Obermaier 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).

  • Electrohydraulic control apparatus and method
    Patent number: 5218895
    Abstract: An apparatus, is adapted to controllably position a movable element in a hydraulic motor. A controller receives a request signal and velocity and/or position signals from sensors. The controller, in accordance with a control scheme using velocity and/or position feedback, determines the flow of hydraulic fluid to the cylinder needed to reduce velocity and/or position errors. A directional valve, actuated by an electrohydraulic pilot system, delivers hydraulic fluid to the hydraulic motor.
    Type: Grant
    Filed: June 15, 1990
    Date of Patent: June 15, 1993
    Assignee: Caterpillar Inc.
    Inventors: Michael S. Lukich, Eric A. Hutchison, Lisa A. Obermaier