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:
Mar. 17, 1998
Filed:
Aug. 30, 1995
William J Janutka, West Allis, WI (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
An improved method and servo control apparatus (C) is provided for controlling the motion of a linear electric motor (A) which in turn generates motion command signals to various apparatus such as a hydraulic steering system (B). Preferably, the servo control apparatus (C) includes a power supply circuit (60), a servo amplifier circuit (62), a pulse width modulation circuit (64), an H-bridge drive circuit (66) and an inductive position sense circuit (68). The voltage at a node (42) between coil pairs (38, 40) in the motor (A) is sensed and synchronously demodulated using transmission gates (222, 224) to develop a DC signal representative of armature (30) position from a center location. The signal on a current shunt resistor (200) is synchronously demodulated by transmission gates (208, 209)to generate a signal, the phase of which is determined with respect to the motor drive signal. The phase signal directly indicates whether the armature is off center towards drive coil 38 or drive coil 40.