Improvement of driving characteristics of the Linear DC Motor Used for the Dither

Abstract

In one of the methods for reducing of the coulomb friction force, a method for adding a dither to the driving current of the motor is proposed. However, how amplitude and frequency of a dither should be selected, has be not made to be being enough clear. In this paper, a dither is used for the drive of linear DC motor in order to realize smooth start up and stop in the low-speed region. As the result, following matters became clear.
1. The dither frequency is mainly dependent on the electrical time constant of exciting coil.
2. If the dither current equal to 50% of main current is added, 36% of the positioning error can be reduced.