Improvement of Precise Positioning Performance by Modeling and Compensation for Nonlinear Friction

Abstract

This paper presents a performance improvement approach for the fast and precise positioning using a 2-degrees-of-freedom (2DOF) controller. In the controller design, effects of nonlinear friction on the positioning performance are especially paid attention, where a precise nonlinear friction characteristic with rolling friction behaviors is mathematically modeled and considered. A disturbance observer with an initial value compensation, therefore, is adopted in order to improve the disturbance suppression characteristic in positioning. The proposed positioning control approach with the friction modeling and compensation has been verified by experiments using a prototype for industrial positioning devices.