Web machine coordinated motion control via electronic line-shafting

Most current multi-axis web machine controllers are not designed to possess the inter-axis stiffness properties which were the inherent coordinating force in historical, mechanically coupled, "line-shafted" multi-axis web machines. As a result, these controllers cannot maintain coordination for all operating conditions. This paper presents the development of an "electronic line-shafting" control technique which serves to replicate and even improve on the historical, mechanical line-shafted properties. This technique was implemented on a five-axis filament winding machine to evaluate such control during periods where the drive was in torque limit, velocity limit, or simply responding to asymmetric load induced disturbances. The results demonstrate that the "electronic line-shafting" technique significantly improves the coordination, robustness and overall stability of multi-axis, web handling machines subjected to realistic physical limitations.