POSITION HYSTERESIS ERROR REDUCTION USING DITHER CURRENTS DURING MICROSTEPPING.

Abstract

This article discusses a technique which dithers the currents in a step motor to reduce its shaft position hysteresis error (the difference in final position when commanded to move to the same location from different directions) during microstepping. Measured position hysteresis errors both before and after applying the dither currents are presented. A 3. 5 in. floppy diskette drive was used to obtain the experimental data, and the position of the magnetic head carriage driven by a size-15 hybrid step motor was measured. Position hysteresis error observed during testing increased with the number of microsteps dividing each regular step size. The reason for this phenomenon is explained.