Robust fast and precise positioning with feedfoward disturbance compensation

This paper presents a feedforward disturbance compensation approach for the fast and precise positioning of table systems. In the micro-scopic displacement region of the table motion, since the friction behaves nonlinear spring characteristics depending on the displacement, the table positioning accuracy may be deteriorated according to the table motion such as inching and reciprocating motions, while the friction behaves Coulomb and viscous properties in the coarse displacement region. In this paper, a feedforward compensation approach for the nonlinear friction is proposed, where same structural mathematical disturbance model can compensate regardless of the displacement regions. The proposed positioning control approach with the disturbance modeling and compensation has been verified by experiments using a linear table system on machine stand.