Cross-coupled contour tracking control with time-varying internal model of a parallel bi-axis servo gantry

This paper presents an integrated control strategy for high precision contour tracking of a newly developed parallel bi-axis servo gantry system. In specific, this integrated control method includes a time-varying internal-model-based controller designed to achieve frequency-varying trajectory tracking for each axis, a disturbance observer intended to compensate friction caused by linear guideways, and a modified variable-gain cross-coupling controller for improvement of contour precision. Various simulation comparative results validate the ability of this integrated control strategy to achieve high precision contour performance.