Robust fast and precise positioning of ball screw-driven table system on machine stand

This paper presents a robust fast and precise positioning methodology for the ball screw-driven table system on machine stand. The position control system is composed of a robust 2-Degrees-of-Freedom (2DOF) compensator based on the coprime factorization description. In this system, a feedback compensator is mainly designed to ensure the robust control performance and to expand the servo bandwidth, where the feedback controller provides the robustness against mechanical parameter variations, such as the variations of load weight and the stiffness of ball-screw corresponding to the table position, and against the higher disturbance suppression performance. The H_∞ design framework should be one of promising approaches to provide both robustness and expansion of bandwidth, by designing the appropriate weighting functions. A feedforward compensator, on the other hand, theoretically designed based on the coprime factorization using the mathematical plant model to provide the desired fast and precise positioning performance. The effectiveness of the proposed design has been verified by experiments using an actual table drive system in industry.