The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 08, 1991
Filed:
Jan. 19, 1989
Shan-chin Tsai, Rockford, IL (US);
Sundstrand Corporation, Rockford, IL (US);
Abstract
A control for a variable displacement hydraulic motor (12) is disclosed. The control includes an electrically controlled hydraulic servo valve (14) for controlling displacement of the hydraulic motor for varying position of a wobbler (28) in response to a servo valve control signal (92); a velocity transducer (72) coupled to a shaft (30) driven by the motor for producing a velocity signal (66) indicative of the velocity of the shaft; a controller (16) for producing the servo valve control signal, the controller including a first signal summer (70) which produces an output signal equal to a difference between a velocity command (68) and the velocity signal, the output signal being applied to an integrator (104) and to a proportional amplifier (76) to produce a wobble position command (82) which is a sum of outputs from the integrator and the proportional amplifier which is processed by the controller to produce the control signal.