Raymond A Gauthier

US Patent:

52277097, Jul 13, 1993

Filed:

Oct 9, 1990

Appl. No.:

7/594833

Inventors:

Raymond G. Gauthier - Soquel CA
Ronald T. Whaley - Scotts Valley CA

Assignee:

Seagate Technology, Inc. - Scotts Valley CA

International Classification:

G05B 1940

US Classification:

318685

Abstract:

A closed-loop voltage feedback system and method for control of the step response of a multiple-phase step motor, wherein the rotor oscillation amplitude is smaller than the period of the back emf voltage waveform, achieving minimization of the step response ringout time. Thus, when used in computer memory disc drives, the present invention provides faster data acquisition by reducing settling time and seek time. The claimed method includes steps for sampling the back emf voltage induced across an open phase winding, producing a continuous feedback signal proportional to the velocity of the step motor, and applying the continuous feedback signal to an energized phase winding to produce damping. The method may also be used in conjunction with open or closed loop position feedback for microstepping the motor to nondetent positions. The present invention eliminates the need for external sensors or an extensive amount of electronics.