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:
Sep. 04, 2001
Filed:
Oct. 29, 1999
Rudolph J. Maske, San Jose, CA (US);
Marc R. Bunyard, Fremont, CA (US);
Peter A. Holst, Castro Valley, CA (US);
Abbott Laboratories, Abbott Park, IL (US);
Abstract
A method and apparatus for driving a stepper motor such that when the motor is stepped, the velocity of the motor is substantially zero upon reaching a new stepped position, thereby eliminating overshoot and ringing, and the wasted energy associated with these effects. The method comprises energizing at least one of the stepper motor windings at a predetermined current level for a predetermined step time, wherein the current level is determined as a function of the step time and dynamic single-step response characteristics of the stepper motor and load so that the motor velocity is substantially zero when the adjacent stepped position is reached. At this point, the stepper motor windings that were energized to make the rotor of the motor move are de-energized, whereupon the rotor is held in place by the inherent detent torque of the stepper motor. Since the velocity of the motor is substantially zero when the adjacent stepped position is achieved, there is no overshoot, and thus ringing is eliminated.