A New Compensator for Servo Systems With Position Dependent Friction

Abstract

In this study, we present a new compensator design for systems with position dependent friction. Position dependent friction occurs between revolving parts that are conventionally used in mechanical systems. Because the friction force changes with the position, the conventional servo controller can not maintain consistent performance. In this paper, a modified Karnopp function is proposed to more accurately describe the friction force’s position dependency. A control methodology then exploits this position dependent friction model in order to cancel out the friction force variation and achieve ultimate boundedness [18]. Experimental results demonstrate that the controller achieves consistently good performance. Based on these results, a compensator design procedure is provided.