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. 19, 1985
Filed:
Sep. 23, 1983
Fred N Chan, Atherton, CA (US);
Ernest E Wuethrich, Santa Clara, CA (US);
Ford Aerospace & Communications Corporation, Detroit, MI (US);
Abstract
A closed-loop system for precisely regulating the speed of an electrically driven rotating body. A tachometer rotor, mechanically linked to the rotating body, is provided with p 'teeth ' around its periphery. A sensor produces a pulse signal upon passage of each of these teeth, to generate a cyclical tachometer signal having a frequency p times the frequency of rotation. A tachometer counter counts this signal and produces a single output pulse after every n.times.p pulses from the sensor, such that the same one of the p teeth is responsible for triggering each of the successive output pulses, and variations in spacing between teeth do not cause variations in the period of the counter output. A high frequency clock is counted by a second counter, which transfers its count to a storage register and resets upon each pulse from the tachometer counter, such that the count held by the storage register is a continuously updated, highly accurate digital representation of the period of the rotating body. A period comparator derives a speed control signal which is proportional to the inverse of the difference between the count and a digital speed command signal representative of the rotational period of the desired rotational speed.