Jeffrey A Shepard

US Patent:

57839395, Jul 21, 1998

Filed:

Jul 26, 1996

Appl. No.:

8/686889

Inventors:

Raymond Lippmann - Ann Arbor MI
Gail Monica Sylvester - Frankenmuth MI
Michael John Schnars - Clarkston MI
Jeffrey Lynn Shepard - Lapeer MI
Ronald Kenneth Selby - Burton MI
James Edward Nelson - North Banch MI

Assignee:

Delco Electronics Corporation - Kokomo IN

International Classification:

G01R 100

US Classification:

324154R

Abstract:

A high frequency AC probe signal is applied to one coil of a stepper motor to induce a signal on the other coil. The induced signal varies in amplitude according to rotor position. The stepper motor is driven by a microprocessor in microsteps. The position of a mechanical stop is determined by monitoring the induced signal while driving the rotor to the stop. When the induced signal no longer changes in amplitude the number of the last microstep yielding movement is recorded as the rotor position corresponding to the stop position. Also by measuring the induced signal at each microstep over a whole rotor rotation and the signal when the rotor stops, a more precise value of the stop position is determined by interpolation. Alternatively, the flip back position of the gauge and thus the stop position is determined on the basis of the induced signal.