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ACCELEROMETER FEEDBACK FOR CLOSED-LOOP STEPPER MOTOR CONTROL

IP.com Disclosure Number: IPCOM000025252D
Original Publication Date: 1984-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 63K

Publishing Venue

Xerox Disclosure Journal

Abstract

Closed loop control of stepper motors has been shown to offer superior per-formance, particularly in the accomplishment of faster settling times, and better, more accurate motion control with less overshoot. However, one drawback of most closed loop motor systems is the relatively high cost of the motion encoder that is required. In the case of drive systems for document scanners which typically have movable scanning optics or platen, the final motion sought to be achieved in systems of this kind is a linear motion which is derived from the rotary motion of the step motor. But here as well, linear motion encoders having sufficient accuracy for the closed loop control are very expensive.

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XEROX DISCLOSURE JOURNAL

ACCELEROMETER FEEDBACK FOR Proposed Classification CLOSED-LOOP STEPPER MOTOR CONTROL
Richard H. Tuhro

U.S. Cl. 318/651 Int. Cl. G05d 13/00

Closed loop control of stepper motors has been shown to offer superior per- formance, particularly in the accomplishment of faster settling times, and better, more accurate motion control with less overshoot. However, one drawback of most closed loop motor systems is the relatively high cost of the motion encoder that is required. In the case of drive systems for document scanners which typically have movable scanning optics or platen, the final motion sought to be achieved in systems of this kind is a linear motion which is derived from the rotary motion of the step motor. But here as well, linear motion encoders having sufficient accuracy for the closed loop control are very expensive.

As a solution to this problem, it is suggested that a relatively common type linear encoder, termed an accelerometer and which, due to its widespread use in automotive applications, is relatively inexpensive, fi.e. approximately $5) be used. Referring to the drawing, the application of an accelerometer 5 as a linear encoder in an image scanning system is thereshown. There, the rotary motion of a step motor 9 is converted to linear motion by means of lead screw 10 and nut 11 to reciprocate the document supporting platen 12 of the scanning system. The output of accelerometer 5 is integrated once or twice by an integrator...